I suggest people look at the CBA FAQ before making intricate proposals.
1. You can trade for a guy INTO cap room (including what you clear w/ salaries going out), OR you can trade for a guy based on an approximate match between salaries coming in and salaries going out. But you can't combine the two ideas in the same trade.
2. The specific numbers for how much salary you can take back are in
http://www.cbafaq.com/salarycap.htm#Q82 The 150% figure is no longer current (it's 175%), but I think that's the only change.
For most purposes of this thread, if you send $Y in salary out (distributed among as many teams as you like), you can take 1.25*Y + $100,000 back in. That's equivalent to saying that if you want to take $Z of salary in, you need to send 0.8*(Z - $100,000) in salary out.
3. There is no longer something called BYC. The remnants of the BYC rule are discussed in
http://www.cbafaq.com/salarycap.htm#Q89 That said, those remnants do apply to outgoing sign-and-trades, even for guys coming off rookie deals (i.e. Olynyk).
The key bit is "the player's outgoing salary for trade purposes is either his previous salary or 50% of his new salary, whichever is greater."
I've said incorrect things on this point in other threads.
Banned temporarily for, among other sins, being "Extremely Deviant".