ZEISS 3x12 monocular magnifier

Im having hardtime focusing with the waistlevel finder on my Hasselblad 503cw. I have the acutte matte D split screen, its good but difficult to see focus even with the loupe thing. (is there a more powerful loupe available?)
I was thinking of buying a ZEISS 3x12 monocular magnifier, just to double check the focus
Have anyone tried something like this?
I have shot many rolls of 120 and I still have not seen any tack sharp image yet, oh maybe one, but that was by accident

Thank you for any help.

Regards
Film lover

Hello,
I think you should try to get a exchangeable magnifying lens for your viewfinder which is adapted to your eyes. An optometrist can help you to find the correct focal length. Any 50 mm standard lens of a 35 mm SLR is one of the best loupes you can get. I'm sure you have one.

There is a Hasselblad chimney finder with diopter adjustable eyepiece. This may be helpful to you.

Thank you guys.
What about diopters, right now I have the standard diopter in my 503cw WLF, is there any more powerful magnification diopter? where can I look after these? I have tried ebay but no luck :/