Your gun has a safety, and that is when the hammer is set half way between fully c_cked (insert an "o") and where it contacts the firing pin. It's called a half-c_ck safety. The thing you are gripping is called a hammer, not a safety. Just details.
In capable hands I'm sure deer could be taken pretty easily with a .35 out to 225-250 yds. I don't shoot a whole lot and I would use the 35 if I knew most shots would be within 100 yds. If I expected to be shooting beyond that, I'd opt for the 243. Just my opinion though.