Air- (Windmill-) Starts with "Soft Start"

So, my old green-stripe ignition modules are no more. With them in my motorglider, starting the engine in flight by picking up speed to windmill the propeller was reliable and without problems. The old modules shifted to the start timing of 4 degrees BTDC at low rpm. The new, soft-start modules shift to 3 degrees ATDC for 6 seconds when a 12v signal is received from the starter solenoid.

BUT, what happens to starting *without* that signal? A start at the normal running 26 degrees BTDC, it seems to me, may fail or result in severe kickback.

Also, while I could be (and have been) in a situation with a nearly dead battery insufficient to turn the engine with the starter, pushing the button anyway in order to get the timing shifted to that 3 degrees ATDC won't supply 12v; with the load, 9-10V is more like it. Will it shift with low voltage?

Thoughts, expertise, or, better yet, experiences would be appreciated!