As said, work out your costs, and what they need to go for in order for you to make your profit, and remember to factor in how much the Mart robs from your pay cheque. Then stick a reserve on them, don't get caught up and let them go for peanuts, you will regret it.
If they look like suffolks, and not hebs then to be honest, i'd just label them as suffolk x and wouldn't mention what it's crossed with.
R.E Ryland x hebs, I couldn't bother. Lets be honest, if you are going to be breeding sheep to sell live weight in the mart, then it's got naff all to do with what you want to produce, its about what folk want to buy. You have to know your market and produce the right saleable lambs.
Out of interest, why hebs as a maternal choice?