True JS - IF I was making my main living from sheep I would go back to Mules - Ive had them in the past, and they throw texel x's that you can finish from 40-50kg depending on when you stick barley / fodder beets on them.... They sell well straight to the abattoir and get good grades so good prices.....
All I want is for my sheep to pay for the fencing on the 15 acres they're on.... and to pay for their extra feed if needed, vet costs and transport and Rent.... Breakeven is the aim.
That means a compromise - getting the best lamb possible out of the breed I most want to keep.... Ideally Id breed pure and sell heb lambs - but to quote one auctioneer "Id rather if you didn’t, you’ll only be disappointed with the price".
Also looking through months and months of auction reports - and speaking to people on here with experience of comercial x primitive breeds, It does look like about 2/3 of the x's produced grade nicely, although are as you say quite light usually 36-40kg. Given that my local auction mart serves part of the yorkshire dales, their are alot of very light finished pure Hill lambs , eg lonk, swaledale, misc horned mixes etc, all which sell - often lighter and poorer finished than what Im hoping to produce, so my main issue is back to selling the unknown really.