Don't worry about it, snail. Not only does practical experience tell you not to worry about it, the science of DMS tells you the same thing.
DMS, while having a relatively low flavor threshold, is really only a problem in lager beers, especially lighter, high-adjunct lagers, where very little is available to mask the cooked-corn flavor. In beers that have more flavor impactors present - dark beers, spiced beers, beers, in short, with more than Pils malt and a touch of hops - DMS flavors if any are masked by the other flavors.
Witbier, with its spices, complex grist, lactic sourness and yeast-driven funk, is one of the last beers you should worry about DMS.
This is one of those bugbears that worry homebrewers way too much. DMS and HSA should be completely stricken from the homebrewing literature and amateur-brewers' memories purged.
In fact, boiling to drive off DMS - which isn't a something you should be worried about - will make an inferior Witbier. A vigorous boil will drive off crucial aromatics. It will also encourage break formation, precipitating in the break the very proteins you worked so hard to put in the beer, the very proteins that remaining in suspension make 'white beer' milky
white.
Cheerfully,
Bob