Rebuild, as in rip it open and replace a few wear / tear parts is actually pretty simple. The biggest challenge there is picking a metering rod / jet combo that will work with you engine configuration. The link above sells a few and how to mix / match what you've got laying around can take a little head scratching but isn't too bad.

Tuning isn't that ugly and is pretty much like any other 4 bl carb with a few additions. One is metering rod height as the base setting impacts idle mix (see also jet / rod combo). Another is secondary air door tension.

The big ugly is the linkages for the choke, fast idle, secondary lock out, accel pump and secondaries. It's pretty tedious and a tiny misadjust can foul it up completely. It doesn't help that there's like 7 or 8 adjustments that are each dependant on the previous adjustment. Your best friend there is another TQ that is set up right so you can stare and compare.

As for finding a shop to deal with it: there are better ways to spend your time. I haven't tried lately but I think finding a carb shop is kinda like finding a radiator shop, maybe worse. If ya do find one, the odds of them having actually heard of a TQ are probably kinda slim. If ya happen across an old timer that remembers working on one, he'll probably cringe and refuse to touch it. The exception being a few of us hard core old timers. There are a couple of shops out in web land that do them right and have a good rep but they'll be pricey.

My advise has always been to roll up yer sleeves and go a few rounds with it yerself.