fuel line connection

Hi yall, haven't posted on here in a minute. Hope all is well. Been trying to get the bike running smooth, however I seem to still have an air leak. With the bike running I sprayed around manifolds, head gaskets choke housing and throttle shaft seals and nothing happened. I can hear the air leak...

Does anyone know if a guy can use only one fuel inlet for two mikuni bs38s since it appears both floats are connected? I'm having a hard time splitting one line into two and keeping good flow of fuel.

In the attached image where the arrows are pointing, are these brass fittings simply for drain lines that merely require short sections of tubing? I disassembed my carbs so long ago that I've forgotten some very basic stuff... Thanks.