No, that's not a good idea. *HLE projects are extremely old and outdated. It's not recommended to try anymore.
Plugins are interchangable between most emulators, so feel free to experiment with ones you already know work well (such as Jabo's).
1964 is getting a bit aged now, so it may be a factor that the graphical issues are what is actually providing your extra performance.
However it's still a very good emulator.
As suggested before, Rice is a good video plugin, as is GLN64.
As for sound: Azimer's is a very good option.
As is his emulator, Apollo (if you havn't tried it already). However with this one you will need to use either Schibo's audio plugin or Azimer's, as the emulator itself does not support sound decoding internally.