I don't have experience with the HK, but I just picked up a Supertuck for my xd9sc. For me, the Supertuck conceals well, and is extremely comfortable while walking around. Mine has less than a couple full days of wear, so it may need some more breaking in, but the only discomfort I have is while driving. My seats are fairly aggressive and the butt of my xd hits the seat and is a bit annoying. I haven't made any adjustments yet. I'm going to give it a few full days of wear to full break in before I determine how much I like it.
I must say, that for concealment, it is far better than any OWB holster I've ever worn.
As for fitment with the specific model gun you have, it is listed on their site, and they have a 2 week trial period where you can send it back for a refund if you don't like it. They also state that if you don't like the retention, you can send it back to have it looser or tighter.