I have sat in 1B and 1C.

From what I could see while I was in 1B, 1A is the seat to avoid in the bulkhead. Your right leg will have good room due to a cutout in the bulkhead wall for your feet. Unfortunately the cutout doesn't go all the way to the sidewall, so your left leg is very cramped. Avoid 1A

1B is a good seat in my opinion. Both legs get the cutout at the floor, making decent space to stretch out. Still can't fully stretch your legs out, but I think the room is fine.

1C and 1D are standard domestic First Class bulkhead seats in my opinion. Feels about the same as a 75X, MD90, MD88, etc. Which is to say the legroom is adequate, but by no means spacious or luxurious.