Carb orientation is not really a big factor, especially carbs with small bowl surface area. Drag race guys run their big Holleys crosswise and roundy car run theirs lengthwise. When every car had a carburetor there were a lot of them being driven in places like San Francisco where the carb was many times at a severe angle with no problem. I'd bet these angles caused more stacking of the gas in the bowl towards one direction or another than any slosh you'd get from repositioning the carb.

Evan