Or a Lleyn; whilst it’s not a terminal sire the lambs do finish quickly and are easily born. Or I have read good things about Charmoise in terms of lambing ease and terminal ability.
What about a Dorset Down, they are medium sized and the lambs grow quickly. A friend uses my Dorset Down ram on her Shetlands and is very pleased with the result.
I am far from an expert BUT have done both the above on Shetlands.
Dorset Down, yes and the carcass is really good. I've eaten my own, as lambs and hogg and I have sold some as lambs, had them done as hoggs (the chap who bought them) and the slaughterman phoned me up after doing them to ask if I had bred them? (Apparently new owner, though 30 miles away from me, took them to the abbatoir, private not commercial, and it's owned by the guy who has bought cattle off me, so recognised the herdmark! Said the carcass was really good!)
Lleyn - now, maybe I did something wrong, I had some Shetlands that turned their noses up at my tups, so i put them with brother-in-laws Lleyn. Honestly, I can't remember how they lambed to him, but I do remember the carcass. I was ashamed of them! They were fatty and greasy, which was very surprising due to the mother's being pure Shetland. What made it worse was that they were for selling. I had these done as the others grew faster (Dorset Down & Bleu Du Maine were my tups) so sold them at auction, but these Lleyns were kept. They still went the year they were born and only on grass, but after that, I refused to use a Lleyn again.
I want to be able to eat the finished product, knowing that the fat is correct. Trust me, picking up boxes of meat at the butchers and getting greeted by excess (lots) of fat is a shocker. I was even tempted to ask if they were my animals but seeing the look on my sister's face, stopped me, as she piped up, "good, not just ours then!" Who needs enemies with relatives like her eh? Apparently, though she liked the Lleyn breed for lambing, she refused to eat it due to its greasiness, and they were grass only, he refused to pay for corn/hay etc. (He was Kiwi, he had different mentality, live on nothing and survive!)