My suggestion would be to switch to Pt-On/Off and make the Window settings like this on both calcs:
xmin=0
xmax=94
ymin=-62
ymax=0
That way, the game will still be the same size on the screen. Display issues might arise, though. The other solution is to just multiply the coordinates so that they fit the 320x240 screen (in 84+ BASIC, the useable area is 95x63 on the 96x64 screen).
I personally prefer the latter trick, because it ensures that the game look will satisfy my needs and it is required for text anyway.