d shay

You are limited by the difference in gain between the high and low signals, the more gain the lower the saturation point, and there has to be a fair bit of overlap between the two signals to combine them properly. A balance has to be struck. For a more technical breakdown on saturation point take a look at Jon Rista's post https://www.cloudynights.com/topic/600061-a-little-confused-about-full-well-and-read-noise/ Also take a look at Dual ADC audio recording which operates in an analogous fashion.

please delete post

Arri cameras do not change gain with ISO level. ISO is just metadata, a ISO gamma curve applied to the same raw data. I think the problem you are having is the result of nomenclature. The Full Well capacity is used incorrectly to equate with saturation point. The saturation point decreases as gain increases.(more gain less "well capacity"). A constant level of gain is applied to boost the signal up to the required voltage. The ADC is designed to match the range of the boosted signal. A dual gain sensor has the two pathways - one with less gain - higher saturation point - and the other with the normal amount of gain.

I'm willing to take that challenge. Arri... hand me over an Alexa 35.

You are missing a step. The problem with photodiodes isn't that they are too easily filled up and clipped, but that the signal is too weak and needs to be boosted. The clipping occurs when the a/d convertor cannot handle the boosted photodiode signal. Dual gain sensors get around this by having a regular boosted channel and a second path with little to no boosting(highlights). These two paths are then combined to get a single image. The signal to noise ratio of the photodiode plus boost is increased by the difference in signal strength between the low and high boost channels.

Is there a link to view the brochure?