Depending on your particulars dillution may not be an option. And I would say dillution is probably not an option for you. Buts its still always a good thing to do incase you can't sub with synthetic for some unforseen reason.
They will not be allowed to watch unless you give them reasonable suspicion that you're cheating.
For me being a male, I can keep the urine at close to 98 degrees for about 3 hours just stuffed in my crotch, so you should do great there. Just practice a little before you do it. Also a lot of these synthetic urines come in a bottle with a squirt to. I highly recommend just taking the cap off when you put it into the collection cup because the squirt tops can make some odd noises when you use it.