Received the float bowl gaskets from PartsNMore, they are too small, not even close to fitting properly. These are the ones I ordered:
Float Bowl Gasket
#20-8032 | Honda CB550K (1974-1976)
Float Bowl Gasket
So I found out via email, that part# 20-5022 were the correct ones, I asked them to correct the website.
I did go ahead and order these to have as backups:
Float Bowl Gasket
#20-5022 | Honda CB550K (1974-1976)
Float Bowl Gasket OEM Ref # 16019-024, 16010-323-315, 16010-323-004
I had ordered a few months ago the Honda o-rings, discovered that I pinched 2 of them during install a few weeks ago. My bench test did not reveal any leaks at the time, but I only let it sit with gas for about 5 minutes or so (lesson learned).
Today I put those 2 o-rings in the freezer for about 2 hours after drying out overnight. I used a dab of grease in all 5 corners to help hold them in. I re-installed all 4 o-rings with the grease. Let them sit for about 30 minutes with gas this time, and moved them from side to side, no leaks.
Also performed the clear tube test and all looked fine to me, so I installed the carbs back on the bike.
Next up, install battery box, battery, and getting my tank primer coated (hopefully weather will cooperate, very windy here lately).