Well I did think about it, and you need a centripetal acceleration at the top of the loop of 2G, which tells you the radius and roll rate (smaller radius = bigger roll rate) at the top, where it is maxed out - the rest amounts to literal "seat of pants" flying to adjust the roll rate sinusoidally until wings level + 360.
... and following through, tell us what radius you would need to maintain 1G as you level out at the bottom of the loop. (Infinite is not an acceptable answer.)