If I was a millionaire I'd buy the remainders and give them out for free...but I'm not.
If we take 15000 we should be well pleased. That's more than double our stadium capacity which even when full takes substantial away support for that to happen.
Its a 3rd of the cities population. Given the amount of people who, don't follow football, don't attend games, support other teams (County, Aberdeen, Old firm and others), then 15000 is probably out maximum threshold at the moment.
People also forget that we are a young club. Just shy of 21. Can't even drink in the states yet. Therefore our support comes from the fusion of 2 older clubs and then new supporters. We don't have an ingrained generation to generation fan base. Many are 1st generation. Falkirk like many others (even county) have longer history and an deeper historical fan base. This helps boost numbers in small towns and cities I think.