Use a random number generator for shipping priority. Easiest and arguably most fair (everyones got their different reasons for getting their's first 
)
)However...
ok ok. no testing. and i'll ship the bulks out first, then everybody else. given that the bulk orders represent a little more then HALF to total orders, i don't think it'll make more then maybe one days difference what order i ship the rest in.
And if it makes any difference:
come on friedcat, accept payment...
The Cat hasn't even taken our coins yet. They're still https://blockchain.info/address/186mfv3sPuQrzmpCgBmVzJBRYDg8HGH7Lx
Maybe there's no more room in the facility for more coins with all the mining. After they ship out our order, the forklift can move our coins in.