danreddingvideo

Thanks for the very comprehensive answer!!  I'm shooting on a GH4, but with the speed booster, so I think I'm cropping at 1.7 ish... I'm also in anamorphic 4:3 mode, so not sure if that effects things too?
I've attached some images of the Helios 44-2... Does the 1st two digits of the serial number reflect the date?  That a good one you reckon?
I'll look into all the lenses you mention!  The lighting advise is VERY useful too..   

 
 

@danreddingvideo You have all good old lenses there.  I have owned all of them and they all flare well.  In fact there's a ton of flaring in your video.  But you're looking for sharp long streaks, and if you want more then you need to look at other lenses.   The older lenses flare because of the old single-coating of the lenses.  But the drawback is that they have a more "smeared" effect and not the sharp lines you're looking for.  Those sharp lines occur more with double or more modern coating on lenses.  But that drawback is you need to have a very very bright lightsource, like the sun.  You can look at some old zooms, like the Tokina 28-80mm F2.8, Nikon 28-80mm F2.8, or something similar.  The more lens elements, the more flaring artifacts there is.  It's hard finding the right combination of taking lens with Anamorphic.
Here's an old test I did with my Kowa B&H 2x (Same as your Kowa 8z).  Strong lights will get the flares you're looking for.  
https://vimeo.com/108202883

I might be completely wrong but it looks like the Helios you have might be the more 'modern' type - has more flare suppression coating on the optics. But it could also be completely due to the light source in the setup. Also if you are shooting smaller than s35 sensor, you will only be capturing part of the Helios' potential for flare - as some of the charm of older Helios models are the 'secondary' rings and rainbows that tend to fall at the edge of the frame. When coupled to anamorphic front, this can greatly add to the overall impact of the 'streak flare.' 
I would expect more flare from an older model such as the 'Zebra' or pre '2' model called simply the 'Helios 44' (simple golden coating) - or the KMZ Helios 44-2 with green and yellow distance markings (this model should compliment your kowa 8z's flare colour the best). These are the better lenses to achieve flares with, as they are the earlier models that have less refined coatings and are more prone to bouncing light inside the optic edges when wide at f2. Having an older model such as the KMZ Helios 44-2 will greatly increase flare when opened up.
Jupiter-9 is a good 85mm pairing to the Helios-44 58mm (again look for older model).Other lenses worth considering (not primarily for 'crazy' flares) are the Pentacon preset type, 14-15 blades ensure circular aperture throughout stops - resulting in constant oval bokeh when paired with your Kowa. The 135mm pentacon f2.8, Meyer Orestor 100mm 2.8 and TAIR-11A 135mm f2.8 are particularly good for anamorphic use. Older Nikkor's flare very nicely, but have fewer aperture blades - so they cut into the oval bokeh quite harshly.Older Olympus OM's are a very good choice too - as they are very sharp, flare is not so pronounced but can easily be acquired to make a nice matched shooting set. 
As for light source, the LED lights in squares will give a blocky diffused streak (as do fluorescent tubes/kino's), best to use a point source (such as the sun for exteriors) or for interiors - a single bright lamp such as a single chip LED desk lamp...or even better a tungsten/halogen light source. A very cheap light to use for some interior shoot's like your example video can be a 'pinspot' - a par-36 lamp that is very pokey and can be easily rigged on a stand or set on the floor to give a shaft of light that you can maneuver to lens in and out of : 
http://www.ebay.co.uk/itm/Pinspot-PAR-36-30W-Black-Lantern-suitable-for-Mirrorball-Includes-Lamp-Stage-DJ-/181599693906?hash=item2a482f6c52:g:y1kAAOSwGWNUV7Wo
There are LED 'pinspot' versions out there that are also good - that have focusable spots, they are lighter to rig but can flicker at some shutter speeds. (but tungsten lamp tends to give a nicer/more natural look IMHO and almost immune to flicker at most shutter speeds).

I recently compared the horizontal flare on the Helios to a Nikon 50mm f1.8 both with the Sankor 16c attached. I found the Helios gave a more subtle flare and the Nikon a stronger 'blue line' horizontal flare. 

I don't know the classic anamorphic streaky look. The Helios is great with the Kowa and the Jupiter 85mm is a perfect addition (they are very prone to flares). If you choose a modern multicoated lens there is much less flare. The thing is though that anamorphics were not invented to produce flares or oval bokeh. They determine the composition and you can shoot with longer lens and get more shallow depth. It is a matter of the subject if you go the anamorphic route or not. But nowadays nearly everything is shot/cropped in 2.40. Not sure if even L. Trier does it now instead of his dogmas (didn't he say they are obsolete?) 

I'm shooting on a Kowa 8Z and am currently using a Helios 44-2 58 F2 as a taking lens.  I've found it surprisingly hard to get flares that resemble the classic anamorphic streaky look..  I've only really taken it out on one shoot, but I've had a play around with is quite a bit and a mate mentioned that the taking lenses will (obviously) influence the shot looks, but I wondered if changing the taking lens would change the flare characteristics substantially?   
Like I say, I've only taken it out once and I was pointing it right into the light most of the time (video below), although obviously not on the silly grade time lapses.  
I've been hunting around on ebay and am considering the following, but can anyone tell me how much difference they're going to make, or show me some footage from a similar set-up?  I'm not unhappy with the Helios, and perhaps it's not flaring because of LED lights in squares, instead of one focussed light source...
Potential Lenses:
Rokkor 58 1.2 or 1.4
Jupiter 9 85 F2
Carl Zeiss Jenna 80 F2.8
Reckon these are worth the investment, or will it make no difference?