I would not go faster than 9 personally for a 22-250.

7 is way too fast for a 22-250.
1:8 would be better than a 1:7.

A 1:9 twist should stabilize an 80 gr berger and thats all you need but you better check it out with some other fast twist guys here.

I forget the link, but a guy had built a 22x47 lapua 1:7 twist, and he figured it was so fast it was actually twisting and deforming 90 gr bergers and he lost a lot of bullets. He had set up the rifle exclusively for 90 gr match bullets.

He went to an 8 twist, still too much then settled on a 9 twist and that worked.