I normaly use a heat gun and scraper which as others have indicated can be tricky.
In order to keep from gouging you have to risk scorching... a fine line for sure and something I would not want to try to do with a wheel like that.
I had a job chemicaly stripping fine furniture once during college and that experience taught me that as long as you rinse in a timely and thorough way with clean water you will avoid staining the wood or messing up the varnishes ability to stick.
I think that would be the way to go with this wheel.
I don't like oxalic acid...too much, IMHO but I know plenty of people who use it and are happy and I am less fussy than most about an even color to the wood.
TSP (the real powder not the fakey stuff in the jug) and warm water is a great way dry the wood out, cutting the oil
in the teak
so the varnish has an even better chance to stick. Be sure to thoroughly wet the wood and then apply it evenly/thoroughly.. I use a soft brown nylon scrubbie don't dwaddle over the piece and make sure it is thoroughly rinsed... just to be thorough ya wanna do a thorough job and I am thoroughly freaked by my continued use of this word...
Anyway.. it'll definately take a bit of patience but how freakin pretty. The results make varnishing worth it still for me though I get impatient sometimes with the prep. Some guy once motored by me while I was putting down a first coat yelling "you sucker, you'll just have to do it again next year" he was pretty hostile...must have been an advanced case of brightwork aversion stemming from a bad experience as a child on his parent's boat.