Help me with wheels!

[Raked 64]

I am finishing up my 64 C-10 and I am stuck on a wheel decision.

I have a 2.5" drop spindle kit/disc brake with lowered springs in the front
and a 3" drop spring in the rear. ( I may add a 1" lowering block)

The wheels I want are the Boss 338 or something similar. The plan was to go 20" all the way around. I am not sure I want to swap to 5 lug. Do you know where I can get the wheels I am looking for in 6 lug?

Should I just "suck it up" and convert to 5 lug? My rear end has been changed at some point. It has a "hole" in the top part of the diff housing for a different style panhard bar. Not too sure that matters unless I do a 5 lug swap. I read the axle splines may be quirky...

Note: The truck is on jack stands and blocks in the picture. Also the motor is out. So the stance isn't accurate.