Good job. With 2 more 45 deg elbows you can move the drain pipe closer to the stand for straps. Pick up a couple of caps so when you make your hole there's room for a do-over.
Even if you accidentally make the hole too big, just plug it with some silicone, crazy glue, chewing gum, or anything that will stay put. Then drill the right size hole next to it. This is, of course, if you don't have another $.79 cap handy
not only does the size of the hole matter, but the length n how deep u stick that tube in the hole affects how much nosie n bubbles.
u need to adjust acordingly.