Bob - I'll be happy to do more detailed pics (supposed to, anyway).... and will. Some of the answers...
1. Engine mounted flat to firewall, no spacers, at about 6". Cowling not a problem going back further
2. HEAD *DOES* clear inside the cowl. Plug cap connector, choke, and muffler need holes access.
3. Operate the choke with a small, straight blade screwdriver. I cut off the "arm", slotted the nylon shaft, glued on a small "collar" of brass tubing so the screwdriver wouldn't cam out when turning. Accessed through a hole in the cowl, it doesn't protrude. Neither do the carb adjustments, just a hole to get to them.
4. Carb arm - clears just fine.

I aligned the motor per the measurements in the manual, life is good. Fits very well.

Cuttting the cowl is very important; there needs to be air getting OUT of that big bowl, and heat build up could be a problem. My pics will show how I addressed that, I hope.

Thanks for the comments.