I had mounted a DFP to a folding table(one of those small ones for eatin at the couch0 and it didnt go so well. I wouldnt recoment it unless you have heall heavy weights keeping it down.
I think as a 15-year-old, you should DAMN be smart enough to calculate from mm to inches and back. If not, you should at least be smart enough to google for a converter. Look at AndroidXP's drawing and check out the measurements yourself.
Depends on the game you're running... Android posted LfS' behaviour, in SimBin's games you get a kind of gear chrunching noise and nothing else, in TD:U you get neutral I think...