Elwood, regarding soundpost location, there is no one definite spot for it, however there's a zone where the best spot could be. In most cases, it's about one square inch.?
First step,?make sure your bridge is where it should be. There are little notches on the f-holes for alignment, think of them as timing marks. Generally speaking, the back of the bridge should line up with the lower ones when the bridge is standing perfectly vertical. When fitted correctly the back of the bridge is perpendicular to the top, whereas the front looks like it's leaning back towards the tailpiece. (I think there's a picture of this on one of my threads) On bridge location, there's no hard and fast answer here... scale lengths vary between instruments, but generally a 3/4-size bass should be about 42 give or take a couple fractions. ?
Once the bridge is located, my general practice is to start with the soundpost positioned so the the *center* of the top of it is about 1-1/4 below the *center* of the bridge's treble foot. Make sure it is standing perfectly vertical. (observe closely, because with it standing between two arched surfaces, there's an optical illusion) Once you've got it there, tune up to pitch and play a little. Take note of any dead or weak notes or any wolf notes. De-tune slightly, more on the G and D strings, and move the soundpost North or South a quarter-inch, and tune back up. Is it different, better, worse? Hint - moving the soundpost closer to the bridge foot will dampen bass response but increase treble response. Likewise in reverse. Another thing to keep in mind, because the top and bsck are arched, the soundpost will tighten as you pull it toward the treble f-hole, and loosen as you pushn it toward the center of the top. Keep the post in the same centerline with the bridge foot. A little bit either way won't hurt anything, but stay in bounds.?
Chances are, moving the soundpost won't make a huge difference on an all-laminated bass, provided it's cline anyway, but it definitely will matter. In my experience, the fit and quality of the post is more detrimental. Too tight, and it will just kill a bass, too loose and they fall out or the top collapses. You can't believe how many broom-handle soundposts I've removed. More than a couple of them were either glued or nailed in. Yes, *nailed*. I found one screwed in one time. Cousin Cletus even took extra time to counter sink the screws. And the basses they came out of just sounded awful. Use only a good spruce dowel. Simple, no substitutes acceptable.?
You will have to have a soundpost setter for this.?
https://internationalviolin.com/ProductDetail/t81_sound-post-setter-bass One of these is a darn good idea too.?
https://internationalviolin.com/ProductDetail/t915_bass-soundpost-retriever On your fingerboard; (this is an easy one) Just get a good ol' rattle-can of black enamel. Buy the good stuff, shake well, apply evenly to a well prepared surface. Cure for a couple days, then wet-sand and polish to a dull luster. (because glossy shows every imperfection) Yeah, it'll wear off again one day, but it's a $5 fix.?
If you're confident enough to remove the ebonized maple board, (and I have no trouble thinking you are) I highly recommend replacing it with Jatoba, sometimes called Brazilian Cherry. It's dirt cheap, hard as any rosewood, and dresses out to a nice orange-brown. (Englehardt uses it now instead of rosewood) While you're at it, take the finish off the playing surface of the neck. If I'm right, your bass is either a Cremona or Palatino-branded import, with a huge neck. Feel free to rasp that thing down to a reasonable profile.?
Sorry to throw so much information at you... email me anytime at my addy here for more specific thoughts.?
