to the forum David. You'll soon be inundated with all the other Daves, Davos, David and (I haven't heard this one since school days) Dabbas welcoming you.
Plus I think you'll find there will be quite a bit of interest in your mirror "construction". Plenty of ATMers here.
NOt having a clue on how to grind a mirror I'll leave the comments to the more informed, but good on you for giving it a go.