I just fixed this. I actually did 2. I had a stab that the previous builder had screwed up the SB on, and vans recommended build a new one. So I bought another completed stab and did the SB. In the process I egged a few holes. Ultimately, with consultation from Vans, I filled those with Cherrymaxes.
However in the process of doing the SB I realized that repairing my original stab wouldn't be that bad. I "re-spar'd" it. Yeah, it's drilling out lots of rivets, but to be honest it was a couple hours with a handful of sharp #40 bits and that was it. The spar parts are cheap, and you can incorporate the SB on the bench when you build up the new spar. I had to used cherry max in a few places because of the difference sequence in a new build vs respar, but only on the inside. From the outside you can't tell. This was much faster, and to be honest, much cheaper than building a new stab.
Drilling the mounting holes is a PITA! Especially if your turtle deck is on. (Mine is a completed plane I inherited). Your best bet is to find a talented 12 year old and send him in there to match drill the holes from below. Barring that, prepare for some bruises crawling back in there. I used an angle drill.
Be super careful you don't egg out the holes, especially on the longerons. Vans is pretty picky on the edge distance on those. I had to repair those on my plane also. After a lot of back and forth Vans and I settled on a prototype repair (I still need to send them back the pics). BTW, if you end up with oversize holes the special NAS 7/32" bolts are $40 each and the only place that has them is Spencer Aircraft. My tail is stronger than it ever was, but it was not a fun job.