Mine arent' silicone. ;c)
As far as suit making -- shugga - if you can tell her where you plan to be on show day that's a start. Also if she makes suits for a living she can probably eyeball it pretty good. The 1 piece suit seems a little more squirrely to me because the 2-piece, you just pull the strings tighter as long as the front fits. Things to pay attention to are whether or not you need an underwire vs. std front, or adding in some cups, etc. If the front fits you right, the rest should be ok.
For all the hair / makeup / nails -- these are things you can scout out ahead of time. I am planning to go to the MAC counter & get a make-over & some suggestions since I'm now a brunette. Nails - mani / pedi, but waiting to see if I want to go w/ the acrylics or not. (Depends on what breaks within 1 week of the show...) Hair - I've already gone to see a guy who did my "look" this past weekend, but my trainer is also negotiating w/ him to have his whole salon come to my show & do hair for everyone (or first come / first serve basis). That's pretty cool because they also have a spray tan service, better quality than mystic tan, which would be awesome for getting face touch ups (several layers of protan will have already been done, but the face always seems to come out paler than the rest...)
Suits -- I still need to meet the girl doing mine.
Shoes - 4 1/2 in heel, 1/4 - 1/2 in platform (i.e. NOT the major hooker shoes) Still need to get thos.
Diet / cardio / training -- all these need to be watched & tweaked. If you have a trainer who can look at you, make sure they are giving you regular feedback and making changes instead of just a broad plan for several weeks at a time. It's called "Dialing in" the program. If you don't have the objective pair of eyes, I'd say take video or pix of yourself every 2-3 days in good light, and doing your poses & scrutinize for areas that need tweaking and also adjust the poses themselves to show of your best features and hide things that need hiding.