What is the minus correction for the eye you use? Your eye doctor will have that recorded on your file. Next step, see if you can see clearly ( even if only part of frame ) through the top part of your trifocals. If you can see clearly then try to get as close to that correction number in a Leica screw in eyepiece diopter. They only come in fixed numbers every 1/2 diopter, i.e.; -.5, -1, -1.5, -2, then a skip to a -3
Only $100 to $110 each. ( For anything to do with Leica, a real bargain. )
It would be advantageous to be at a well equipped Leica dealer and just try the various diopters until you find the one that works best. But that is not always possibile.