The Sinclair heavy varmint is more than adequate for what you'd be trying to do with it. The other one you are looking at I don't know anything about but given the option between the two I'd get the Sinclair just because it is from Sinclair... that's a lifetime purchase.
If you are shooting 100 yds for load development work... Personally I don't use really much of the adjustments that are available at that kind of distance. So it is overkill really for that use.
