One of the advantages to fretting the instrument after the neck is installed with the fretboard on the neck is we can level and shape the fret plane independent of what's under it.
Also
I have a tutorial here on the OLF that countless people have used to eliminate the dreaded body hump which is what you have. It's called Flattening the upper bout if you want to do a search and see how that works. I still get PMs frequently from folks who tell me it works like a charm and it did on my Heshtones too.
Nothing wrong with Titebond original for attaching tops and backs and it's reversible, decent open time and again... if you are not perfectly set up for HHG use and respecting that short open time it will fail sure as shootin. HHG is marvelous but disrespect it's very narrow open time and it will bite ya. I know of a builder who gets $35K for their creations and they use almost exclusively Titebond Original.
So if you go the wedge route keep in mind that your neck angle in respect to the top and bridge needs to remain appropriate so you don't end up with a super tall or low saddle or bridge and have other issues that in the case of a very tall saddle will shorten the useful life of the instrument and encourage a bridge to lift.
Back to flattening the upper bout I believe at the time I wrote the toot that Martin did basically the same thing too to smooth out the transition of the fret board onto the body and not get any body hump. The technique also automatically creates about 0.010 - 0.015" of fall-away which is also very desirable.
Lastly early guitars are learning experiences and they need not be perfect but the real opportunity is what we learn for the next one so that these kinds of issues don't happen to us again. My first guitar was so bad looking.... that I put it out with my trash one Sunday night and I propped it up so people could see it with the hope that someone might come along, check it out, want it and take it. It played OK it was just not very visually appealing and it was a StewMac dread kit. I built it in a Residence Inn in Sunnyvale, CA where I was assigned to work for my day job.
The next morning when I went out to go to work someone had taken it out of my trash, checked it out, perhaps played and then threw it in my yard and left it.
Everyone is a critic
And really, really lastly although I encourage folks to learn repair work there is zero value in having to deal with a body hump. You will never deal with it again, it's not something that we have ever seen in the commercial world as something someone wants us to fix nor would we it's simply a slog and your best play is to get it over with and move on to the next one using what you learned here as the real value.
PS: My first had a body hump too.
