When in doubt, round down.
Having the spokes sitting perfectly flush with the bottom of the nipples is neat, but there is little, if any strength to be gained by achieving that last bit of perfect fit.
OTOH using spokes that are too long will expose you to the risk of running out of thread before you've reached the recommended spoke tension, and that'll compromise wheel durability far more than a few empty threads in the nipples will.
hub, gear , nongear
front, 293, 291
rear, 291, 292
I don't get that gear, nongear reference, but given the choice(and assuming 2 mm increments) I'd go for front 292/290, and 290/292 rear.
I would consider using 292 all round a bit of a gamble, but less so than 294.