What's your seismic risk class up there? I think we're a C in North Ga. Wind exposure class is the big factor in selecting tie-down anchors. Earthquakes don't usually make the building want to fly away...

And I'd use a second drill for the countersink holes. Not many SDS bits for wood - no call for them.

You could use a standard spade wood boring bit for the c/s in your basic 3/8" drill.

I've run most hammer drills off of a 2000w genset. Very few draw over 13-15 amps, and the only one I ever used that did was a 60# pavement breaker with 'lectron power instead of air.