The OS 35-S weighs 6.7 ounces
The OS 30-S weighs 7.1 ounces
The timing on the sleeve is .005 thou lower, or more duration ,by about 2 degrees, in the 30, both intake and exhaust, are slight more duration
As I stated the 30s always seem to have a tighter piston fit, Turning the same prop, it is about 5% differance in power.
And No you can't compare the venturie version to one with a carb
The additional weight is of course in the sleeve, both will fly a Nobler or Stilleto very well
Randy