Trump will have at least 300 hand picked delegates, Cruz will have 200. The rest will be picked at conventions etc. I estimate at least 75% will be conservative activists.
I will remind you again the Iowa SoS ran for a delegate in the 1st district and didn't make it in favor of three Cruz supporters.
Where is it written that any bound delegate has to vote for a rule favoring his assigned candidate? Do they use a Vulcan mind meld to transmit orders to these delegates?
This is where the fix is in if Trump comes up short of 1237. Count up the number of party hacks among the delegates; if it’s over 50%, then payoffs will assure adoption of a rule opening the door to Kasich.