You give too much power to the GOPe in a contested convention. Between Trump and Cruz, they will have I'm estimating between 1800 and 1900 delegates in the first round of voting. The GOPe will have much less. The question is how many delegates will the GOPe control after the first round. Since you think that the GOPe will be able to "select" the nominee after the first round, perhaps you can answer the question, state by state, how many Cruz and Trump loyalist delegates are there?
I don't think the GOPe will be anywhere near controlling 1237 delegates, even after the second or third rounds. Thus the GOPe is in no position to "select" the candidate. At best they will make a deal with either Trump or Cruz to select the VP.
About who I am for and against and why, the short answer is that I am for Cruz over Trump because Cruz is anti amnesty and understands the Constitution. Trump comes up short on both.
I can't prove to you he's not those things. I hope time won't tell, but if it does, I'd be happy to be wrong.