Hi Burnin since you'll be launching soon the ordering website I'd like to suggest a way to avoid and ordering/preordering/chip-batch matching mess (like what happened with KnC).
All chips come from batches and all batches are time-stamped so once you figure out which group buys are interested in your services, it should be very easy to organize a queue based on batch ordering date. It'll make sense for example if you open orders by turns to specific chip-batches based on ordering date, instead of opening for everyone at once and flooding the website and having to match orders to chip batches afterwards.
For example you first open order books for Zefir Batch 1 from April 16th (assuming this is the earliest one) for like 3 days or so, then you open order books to the next batch based on ordering date, and so on and so forth...
If i remember correctly then burnin stated that the order of assembly will be the payment time of assembly, not of chip ordering. Thats the first paramater. The second is when chips arent there yet then later orders are processed first. For example someone bought assembly for batch 7 in zefirs groupbuy and batch 5 isnt with burnin yet then he starts to create miners for the chips that are already there but paid later.
I think thats a good solution without problems.