Here are some problems I see right off the bat. For one thing fingers are a bit harder to shoot, not that it can't be done because people have been doing it for thousands of years I suppose. I for one am not very good at it. However if you are shooting an older bow without a cut out riser and with fingers there are some things that need to be considered. One, spine is VERY important. You need the arrow to flex around the riser at the correct time in order for it to miss it. Number two, I don't think you have the correct rest for your set up. I would think a plunger rest or something with some side pressure would work better then a prong rest. And number three I think you would have better luck with feathers instead of vanes with that set up. You most likely have some sort of contact issues with plastic vanes.
These are all guesses of course, there is no way to really know without seeing your set up or you shoot.
I wish I could help you more, but the honest truth is I don't have that much experience with these older bows and I have never shot fingers. I was hoping one of the more experienced guys (older

) would help you out. They could most likely suggest a better set up as far as a rest and the correct arrows and the such. Arthur or Len would be great if you could get them to respond, maybe we could PM them or something.
I know for a fact your bow is capable of shooting well, people did it for years and years before the newer bows came out. Infact some did it better then the guys do now with the newer bows. But you are correct a newer bow might solve some of the problems, but sometimes it brings a whole new set with it.

. Even if you did get a newer bow, I would still like to see you get this one set up so you could shoot it better. And if you get a newer one, especially a shorter one, you might want to think about using a release.
Lets see who esle responds to this and maybe I will contact someone with more knowledge on these set ups to help you out. You could also try posting something in the traditional section, someone over there may know since the set ups more simular than a modern compound.
Or maybe rename the post to "help with an older bow and archer" or something like that. Lots of guys just zip past the posts about which bow is better and that sort of stuff, I almost did. All the newer bows are pretty good, it just depends on what you like is all.
Good luck,
Paul