Jake, anybody lucky enough to ride as much as I do will go just as fast, if not faster.
Just to comment on your bike, IMO it's a great bike, you only need some minor adjustments, such as:
- lower tire pressure, you're not that heavy (I hope I don't sound like too much of a jerk...) and you'll be amazed at the difference it makes. Tubeless?? Go the el-cheapo route to try it out and see the difference.
- handlebars: the bike fit me, but trying to pedal standing up is harder. Try just once flipping the stem over (bar on it and all) and putting it at the lowest position on the steerer and feel how weird it is. It should not take more than 15 mins. tops given that you have lock-ons and no shifters. Ride around the block then revert to the original position. Then work from there until you find something that suits you best. It's a myth to think that it's bad for the back, it's quite the opposite, but by going too fast you may put too much strain too soon on "untrained" parts of the body. However someone your size should be able to go fairly low and reap huge benefits: better traction on the front (as Norm pointed out), better weight distribution on the tires (cf. tire pressure), more leverage when going over obstacles, you can take more advantage of upper-body strength when climbing, and so on...
One thing I noticed, and was fairly surprising, is that the mary bars tend to make your hands slip towards the bend at the front, and that, even though I couldn't put too much pressure on the bars since they're so high. Don't know if anybody noticed that, but I like to keep my hands relaxed down hill even at speed and mary bars didn't seem to let me do that. I'm speaking of the downhill on the orange trail towards the green rooty trail, that's probably one of the most "technical" descents in that park 🙂
Walter's setup sounds sweet, I wish I had tried it out.
Good luck!
Maurice