Hi Darren if you first post a build thread you will get a lot more people post answers rather than aksing in an old thread . Secondly have a look through some of the other helmet build threads, seeing what others have done gives you a lot on insight into how pieces fit.
Ears are the worst to make fit, take your time and sand a little at a time, less is more
I never worried about the bolts inside at first I just trimmed them down so they didn't stick out too much, I now have a block of foam either side which covers the bolts, the foam stops the helmet from wobbling around. I aslo glued velcro on to the back of all my foam so I can take it out after sweatty troops and wash them.
If you use the lense film there are lots of ways to keep it in, hot glue, tape, silicon, no one way is right, it's what ever you are good with, some don't trim the lens and put a full rectanle in, I use a firm lens, cut to suit the eyes and fitted with hot glue .
Oh and a curvy straw may help your drinking problem