The bolt pattern should be the same...either will work..I once put a Walbro SDC80 on a G62, way big, ran the same..
If you believe the conventional wisdom that a larger carb makes the engine run better use the Walbro..Since the bolt patterns are the same you could test both..I tried 3 different carbs on a G26, from 3/8 to 1/2, they ran the same within 100 rpm..did the same test on a US 41 and a G62, same result...So much for conventional wisdom..