We used a 930f flex head on our 9610 for wheat and it works fine. If the crop is really thin which I dont think is an issue in the states the heads can fall out the front.
The best setup for wheat is to run a string line across the front and adjust platform so its locked up in the rigid position and adjust level of the platform so the knife is as straight as you can get it. Replace any worn knives which will ensure a nice cut and better ground speed......set up the 9610 by grabbing a handful of grain & throw it over the bottom seive adjusting to where the grain starts to fall through. Set the rest of the cleaning section as per deere specs and you should have a nice clean sample in the bin!!
We just bought a 936D for our 9610 and personally I dont think I will use the flex anymore..the conversions are really easy!!
do yourself a favour and get rid of the 900 series. 630 hydra flex best front ive had. goes just as hard in wheat as my macdon because of the better cut. 635 were prone to vibrations and cracking as well as bouncing the reel up and down giving your fingers a trim. If you dont want to spend the coin on a pressure kit for the combine just remove the valve on the right side of the front and put a 3 way tap there. Then you can adjust the pressure with the reel hight systme then lock it there. I wouldnt expect much change from about 6 grand to do the whole genuine conversion.
Would an air reel help when running a flex head in short wheat? I would think it would help push it back under the auger. If it does work i would think that would be cheaper then 2 heads also farmerjones.