This thread is so full of estimations run wild.
A bird someone says is 16-20 lbs will end up weighing 10-12lbs and a bird someone clames as 3' will turn out to 27-31". Funny no one offers hard proof for height and weight. Very reminiscent of a fisherman's tale.
That said. Pedigree lines...
That would be a cool cross JRnash.
One of the parent breeds to make the cornish was the Malay.
Here is a picture of a 5 month old cockerel who's a jersey/japanese oriental cross (50/50). He's absolutley huge for his age but he doesn't resemble the jersey at all :). IMO, crossing any...
It would still look like a malay but have minor jersey features. Waddle, flatter back. The oriental game genes are very prominent. You'd be best to use a 75% jersey/25% malay to cross with another jersey. Even an 8th malay would be obvious.
You'd end up so far from a jersey that it wouldn't...
Don't know seeing as these are still a "prototype" but parent breeds mature at 13lbs or more and all are 27-33" tall. They are already taller and heavier than any of the parent breeds were at this age. I'm hoping 33" +. I don't think they'll disappint