Hi Ryan
There are a couple of issues here – accessing the viewfinder comfortably and then focusing.
A right angle finder would help you look through the viewfinder without uncomfortable, physical contortions.
In terms of focusing, I have used a
Stellar Technologies system previously, with some success although I am left wondering how well a Bahtinov Mask might be for focusing?
http://www.iceinspace.com.au/forum/s...ad.php?t=38247
http://www.iceinspace.com.au/forum/s...ad.php?t=35676
http://www.iceinspace.com.au/forum/s...ad.php?t=47090
Cheers
Dennis
EDIT:
I would also suggest that you seriously consider whether you should make any further investments with 35mm film astrophotography – it might be a dead end?
I’d look for a 2nd hand DSLR, preferably with Live View, as the feedback/improvement cycle is immediate, as opposed to waiting to develop and print film negatives.
Cheers
Dennis