So for you competition shooters have you had to modify your holsters to comply with the belt rules? Does a standard blade-tech DOH meet these rules? How often is this type of thing checked at a major match?
No; sometimes; occasionally when an RO notices.
I've never had to fix one---but I know plenty of people who have, because the BladeTech DOH (which I used to use) sits differently on people with different body types. For many, staying within the rules is no problem. For some, it is a problem.
It isn't normally "checked" at a major match like there is for an IDPA equipment check, but ROs and CROs on various stages DO look at your equipment, and if something seems wrong, they'll officially check it. (I note that using the Tek-Lok instead of the SR loop pushes the holster out even further, leading to more problems.)
I can counter act the amount of outward cant when I make the holster but it also eliminates the point of the DOH.
Truthfully, it makes for a better draw when the gun is still vertical, just simply offset from the body instead of having it canted outward from the body (to get an offset at the top). Having it canted outward actually makes for a harder draw. And it doesn't need to be offset from the body much---enough to get the thumb around the inside without hitting anything is sufficient.
There' s a reason why a LOT of people are now using Ben Stoeger's BOSS hanger for their holsters---the offset is adjustable, the holster doesn't move AT ALL when you move around, and the gun itself has an adjustable forward/backward cant so that you can set it perfectly vertical for the best draw, even if your belt isn't normally perfectly straight horizontal.
This link is for the full hanger/holster combination, but you can get just the hanger if you already have a holster pouch that works with it:
http://benstoegerproshop.com/bsps-boss-dropped-offset-doh-holster/Short form: BladeTech DOH works for most people, especially with the SR loop. (Tek-lok adds more distance, MUCH more often giving a problem.) For some people, however, it is too far according to the rules, and at some major matches this may be a problem.