I don't understand why if you calculated spoke length based on flip-flop, your DS spokes are too long. If anything, I'd expect your NDS spokes to be too short.
No harm in trying to re-dish the wheel, but you may run out of adjustment space on the spoke threads.
you may run out of adjustment space on the spoke threads
Trigonometry says you get a lot of dish for a little change in effective spoke length, so this is unlikely unless you're already very close to the limit
I don't understand why if you calculated spoke length based on flip-flop, your DS spokes are too long. If anything, I'd expect your NDS spokes to be too short.
No harm in trying to re-dish the wheel, but you may run out of adjustment space on the spoke threads.