For almost all companies, whatever order you send the cards in/list them on the order sheet will be the order they’re graded in. I believe PSA will even charge you a fee if the cards are not submitted in the order they’re listed on the submission form. So as long as you put the one you think has the best chance of a 10 in the order you want it graded, that’s the way it’ll come out. You can’t make any requests to alter the order of the cards (e.g. if one gets a 10 and one gets a 9 can you put the 10 in order with the others). Hope this helps!
I think BGS is an exception. They do not like the order you enter, in fact there are huge problems that few have noticed when using an middleman. Suppose two people send the same card, both are practically identical, one takes Black Label and the other Pristine, you won’t know which one is yours. I tried to ask an official BGS middleman how they know whose card it is, their answer was there is no way. They, to avoid this problem, for each pack there are only different cards, so if two people have some identical cards, they divide it into another pack. While the unofficial middlemen say they “take pictures” to recognize the difference, a very unprofessional method.