Big wing, small sail
Dean (CoreAS) in Texas has light wind foiling dialed-in with his Infinity 99, Wizard 125 and 5.8 wave sail.
It seems that he easily gets going in 8-10 knots, not a whitecap in sight

Small wing, big sail
Tried the 99 and 84 but prefer the speed and maneuverability of the Infinity 76 in the ocean, so that's now my biggest wing.
To bring the low wind limit down similar to the 84 (for me a crappy pumper and W105, about 10 knots), I've upped sail size from 5.9 to 6.5, which I think is probably the biggest size I'd want to use to ride swells.

Stoked with the Enduro 6.5, rigs on a 430 RDM and 2m boom, pulls like a train with a super relaxed feel, but also pretty light so works great on small waves and wind swells. And no annoying batten flick mid-gybe that you get from a cammed sail.
Other benefits of a bigger sail in the ocean in light winds and chop - more sail pressure helps balance when grovelling and during tail-spin gybes, also easier to water-start.

So 2 ways to go I guess - interested what other freeride foilers are finding the best solution to have fun when it's light?