For H5, the first thing that springs to mind is the print scale.... when printing pdf files it's quite common for adobe (or whatever application you use) to scale the page down slightly before it prints. Even a 10% reduction would make a big difference when working with such small blocks.
As for the triangle, I look at the pattern and while it looks fairly involved, it seems like a methodical block to do. I'm intrigued now (and more than a little scared!) so I've printed it out and I'm going to see if I have any trouble with it.
Photos would be good, someone may be able to see why it's not working for you.
And this is exactly why doing the DJ together is so awesome, because we can help each other when we get stuck. :-) The circle ones are giving me nightmares, I've never done a curved seam (apart from applique) so I'll be needing a pile of you to hold my hand when we get to those! lol