Ok here is how we build our systems.
First Note: Do not hang a heavy mixing valve set up off your carburetor, most likely what will end up happening is you will break the bolts from engine vibration. This adapter is so you simply adapt a hose to the engine. Set up your mixer valve remotely on the generator with a hose connection between it and this adapter. The mixer valve is as simple as a pipe tee with a ball valve for metering in air and just an open connection from the gasifier. Im assuming you already have shut off gas supply valve in order to flare the unit.
To mount the Tee build a plate that you can bolt to the generator and use U Bolts to mount the Tee valve to the plate.
If you can build that gasifier I have to assume you can build this adapter. This adapter is well proven and bullet proof. To make things simpler you can order the flange from McMaster Carr or compromise and make it your self. Bellow are illustrations how to build this and set up to carb.
You can order the Flange here: McMaster-Carr
I would use 1" NPT fittings and use a cut section of 1" pipe for the hose adapter of the face plate. Then 1 3/8: ID hose will fit to make the connections.
If you want to automate the air fuel mixture I have a tutorial on here using the AEM sensor kit. I have new code available and this set up is very stable with the AEM kit. Other methods with out cleaning up the O2 sensors input signal and amplifying it will not cut it for this. The AEM kit does this and it does this very well; much more so than you can trying to do it yourself. Its just worth the extra money, our mixer controller is very stable. If we have a stall its generally not the mixers fault something most likely to do with the gasifiers output.
Link to tutorial