Thinking I'll go premix. It's more guaranteed that you've got oil in your fuel if the fuel contains oil at all times. I've had enough premix bikes and have never forgot to add oil. The pump has always worried me.

So, at a 30:1 mix, 1/31*150 (where 150 is, for example, the current hyperthetical jet size = ~5. So going up about .05mm in size, i.e from 150 to 155 sounds about right, atleast mathematically.