You'll be sweet man
Dont think the spigot bearing off a 1300 will fit.
Yea lock the choke open/take the butterflys out. I run no choke and its sweet, less chance of it running rich and fucking your engine. Just means you have to keep your foot on the gas to idle until it warms up.
Do you have a pic of the bolt going into the back of the inlet manifold? I have a few different ones, if yours are the same as mine I can probably find one that comes out at the right angle, either that, or undo your one, put some thread tape on it, and then do it back up and hope it tightens half a turn ealier or something.
And not sure bout the fuel return? I dont think my 28/36 has one