Texels are very hardy. If you can get one that's not too huge across the shoulders and buttocks for your young ladies. And has good feet.
Alternatively, a really shapey Shetland tup would give you super breeding girls, and the males would still be appealing at the mart.
You might have a job sourcing as they're now so rare, but the traditional tup for Cheviots was the Border Leicester, or 'Bred'. Known as 'the great improver', they tell me. The Doulton Flock is the flock I know. Wonderful strong animals, and fabulous fleeces.
Or a Downs breed. People seem to rate the Southdown, and the Hampshire Down, as terminal sires, and as fathers of breeding females.