Still out here too.

I do not have the Saito 325, but the ASP FT400, and yes, using the stock glow carb, with as only modification WRT carb the main needle O-ring, plywood thermal isolators between engine block and the carb/header.
Since at low RPM the ASP, because of the layout of the intake arrangement suffered from oil separation in the intake tract, causing the vast majority of the oil only reaching one or two cylinders, I drilled a few cheater holes in the header elbow that at low RPM (high intake vacuum) blow back and atomize that oil towards the centre of the intake.

I am using indeed muffler pressure, and provided the tank is as short as possible behind the firewall, this allows a totally troublefree fuel supply, from idle to full throttle in all orientations.
It runs idle with the nose vertical, and will accept full throttle from that position without issues.

the fuel mixture arrangement is the one as discussed in the "electronic mixture control" thread, which also functions flawlessly.