To some extent the innie outie thing is a question of luck....
but if you want it to be a nice @ shape (if you know what I mean... a nice spiral) then your best bet is cord clamping not right at the skin.

My independent midwife cord ties using sterilised home woven wool and it is tied of at the end of about 2 inches of cord (so not at the skin). You just spiral the bit of cord around regularly and let it have a bit of air time. It dries quite quickly (can be a bit smelly) but it always ends up a lovely neat spiral and our daughters is an innie.

The other bonus of having it tied this way is that there is no uncomfortable large plastic cord clamp against your child's skin just a soft bit of wool and the drying cord.

I imagine most obs would think this is unsafe in some way though (even though it's just as sterile). Good luck!