For the purpose of discussion I would offer a different proposal, in that the first competition for arguments sake the 2016 winners of the right to be promoted do not go up to the elite division the following year, neither do the relegated team drop down, the transfer of the two clubs happens the following season 2018, but the funding adjusted to enable the promoted club to build for the promotion, subsequently the 2017 season sorts the candidates for P&R in 2019, and so we go with the 2 season cycle.
You don't give me time to think!
On reflection I can see what you are trying to do i.e. minimise the effect of P & R.
But I can't see clubs or fans wearing the wait to go up or down.
I also don't think "preparing for SL" is a matter of a club playing a further season in CC so they can sign up players, the top 11 will still take the best and the promoted club will be faced with trying to take players off the demoted club.
I cannot see a way around the split, apart from this one..............
All clubs are allowed the same salary cap, then as soon as the Championship club has mathematically won CC through league leadership, they are then allowed to double their cap.
So if a rich club has it sewn up by August they can sign up players to truly be able to compete the following year.
That's the best fantasy I can do and that will never ever be voted through. I fear any mechanism that makes it easy for a Championship club to take players off SL clubs just won't get the vote.
It won't get it from me either (not that I matter), I do not like clubs wasting money on inflated wages.
I'd just go for even cap between the divisions, a club may go up and down a few times but eventually they may well stick. They would deserve to as they would be showing perseverance and adequate financing.
Isn't this what happened with Fartown when they were always bottom, went down and managed to get back up and stay up.