Unforunately there's no such thing as a light 60. Closest thing to one would be the MDS 58 and that weighs a good 4 oz more than 46s from other manufacturers.

IMHO, the 50SX ain't worth it. Put a Tower 46 pipe on a 46FX and you're looking at the same power. Plus it's ringed which means that it'll take longer to break in. Not worth the extra $50...

Within this size/weight range, you're probably best off with a Jett, but if you can't afford it, there are plenty of very good alternatives. Check out the Webra 50, Irvine 53, or MVVS 49. The displacement advantage of these European engines means that all the above will outrun a plain jane Asian 46...