Upgrading a decent classical guitar?

[Doctor7]

Hi all,

Yesterday I bought a Yamaha G255-S from 1979 in excellent conditions (£300). I know they have very good quality solid spruce tops, so I believe they are good candidates for some improvements. Some of them are quite easy to do and I will do them myself, while others will require the expertise of a good luthier, hence my questions.

The easy and quick improvements (I can do them):
a) Replace nut and saddle from plastic to either unbleached bone or tusq. The saddle seems to be glued, so it might take some time to remove but I'll see.
b) Refret with taller frets to improve playability (more forgiven, easier to perform vibratos)

Not so quick or easy, but still could do them myself:
a) The neck has a chunky D profile, and I prefer a smoother C profile. This would require re-shaping and refinishing the neck. I can do it (am starting to do French Polish on a few guitars, not the full instrument, but necks for example), but would reshaping affect the tone?
b) Refinish the top with French Polish (removing the thick polyester).
C) I will experiment with making a 3D printing (using a material that is very similar to wood) of a combined tornavoz (to help lower the air resonance) with an extended fretboard (20th fret) that can be retrofitted into the guitar. This will be a fun experiment!

Hard, which will require the expertise from a knowledgeable luthier, which I am obviously not, but this is the change that will be by far more effective:
a) Improve the responsiveness of the guitar by re-working the bracing, and perhaps making the top thinner. Is it possible to re-work the bracing without removing the back, like with mirrors and the like?

Considering the quality of the tops, I believe these guitars could turn into decent concert level instruments, but the work required (money and time) might not be justifiable.

I am learning quite a lot by doing some work myself and am happy to engage on this, for my own learning experience and to get something good as the end result, but removing the back (and possibly destroying the binding/purfling) and working on the bracing is something I am definitely not comfortable with.

I have some very reputable luthiers nearby within an hour reach (Simon Ambridge and Kevin Aram, for example), but I doubt they would be interested in doing something like this

What are your thoughts on the subject?

[printer2]

Good luck.

[redir]

If you plan on refinishing the top I would suggest you don't touch the bracing till that is done. You will probably notice quite a change after doing that.

Good luck.

[Doctor7]

Originally Posted by redir

If you plan on refinishing the top I would suggest you don't touch the bracing till that is done. You will probably notice quite a change after doing that.

Good luck.

Thank you all. Just an update:

I will hold on with the idea of re-shaping the neck. It's OK and I will get used to it and maybe even like it, so it is not a priority at all!

I have done refrets in the past and made nuts/saddles, and just found out that the nut was already replaced with a bone unit, so I am good on that. Just need to replace the saddle.

I have heard different comments on the finish: some say it is not worth the effort, while others swear by it.

I will think about it and keep researching.

Cheers,