I think I am very much old school when it comes to squad numbers. If a player has a preferred number then I will assign that to them where possible. I tend to assign my best starting 11 for the numbers of 1-11 and the same applies for the subs from 12-18. Apart from that I tend to keep the allocation of numbers to:
Haha I do the same thing with the randomness after I'm done assigning the numbers I want to. Sometimes I'll assign a real life number of one of my favorite players to a player in the game that I really like.
And then just continue, 12 RB, 13 LB, 14 CB etc. But I often give 13 to my super sub but the rest is usually the same. I usually don't hand out 1-11 right away to new players though - I usually let them earn those numbers.