Carburetor jetting for high altitude

[Stroker Deuce]

New owner of a 800 Drifter here.

I do most of my riding at between 7000 and 9000 ft above sea level.  Typically on Mikuni carburetors this altitude would require about a 15% smaller main jet than sea level, unless I did something else.  I'm more familiar with vintage two stroke dual sport bikes with Mikuni round slide carburetors.

The something else I have planned, is to Grampsize the bike. The recommended main jet after the Grampsize procedure is 170 at sea level.  Sooo, using the SWAG method my starting point would be about a 145 main jet or about 15% less than the recommended 170.

I haven't a clue where to start with the jet needle or the Pilot jet.  Any sage advice with this situation would be greatly appreciated.