I have found that only the glow carbs with a very fine thread on the needles can be used with gas, other wise a person has a very tough time finding the correct tune.
I just finished up a Saito 270 twin where I used the glow carb and so far it seems to be working ok, but I think a walbro would have been better.
At a 16-1 - 20-1 ratio the clean up is no where near that of what 18-20 % oil is in glow fuel.
Making an adapter for a walbro type carb has proven to be the best route to go and so far I have not had and issues finding a suitable carb for the conversions I have done.
Here are a coupls of pics, one is a 160 FX and the other is a 160 FT twin. There was not enough room for the carb on the twin to lay down so I turned it up right, something like the larger gas engines are. Both engine's run great and are able to swing the larger end props W/O the lag they had on glow fuel. Both are on 20 -1 gas oil mix