Push For Closed Republican Primary: Who is behind it and is there an ulterior motive?

Last night I made the following post on Facebook "Open or closed primary? Does it really make a difference? Pick your poison. With an open primary yes could get Establishment Republican's and/or moderate Republicans that despise Conservatives, to work with Democrats to give us a Moderate or RINO (Republican in name only) candidate. With a caucus or convention what is to say that again that Establishment Republicans /Moderate Republicans fill the delegate slates shutting out conservative Republicans and in turn pick another moderate or RINO candidate? By going the convention route you do shut out the general public and many donors. Will they be willing to donate, if you shut them out of the process?"
There seems to be a concern that with an open primary that an establishment candidate could get the nod in Michigan due to Democratic crossover vote.  Establishment Republican's in the past have courted Democrats to help them block conservatives from winning an election, such as the failed attempt last year in the 107th State Representative race between Chatfield and Foster

Now there is a push to close Michigan's Republican Presidential Primary, to prevent cross over vote.  But who is

Is John Yob of Strategic National working on a closed
Republican Primary to assure a Rand Paul Victory?

behind this push?  Many are saying John Yob of Strategic National, who is representing Rand Paul for President.   

Rand Paul is a favorite amongst many Libertarians and their Group Campaign 4 Liberty, which also includes many Republican Conservatives.    While Libertarians, Conservatives and Republican's share the same fiscal conservative values, Libertarians are considered social liberals and many believe in deregulation of illegal drugs, and

Republican Presidential Hopeful Rand Paul

non-traditional marriage.

The push being put onto Conservatives is that they must have a closed primary to keep out the RINOs (Republican In Name Only) that would want to put a moderate Republican Candidate up, such as a Jeb Bush, by inviting crossover Democrat votes.

But having a closed primary doesn't prevent this either.  If the Republicans go the convention route and have delegates choose the next candidate, who is to say that the slates will not be fixed?  If the Establishment takes control of the voting slates, couldn't a Jeb Bush still be elected?  

In the current push it is rumored that John Yob, and his firm Strategic National, believe that they could control the Slate of Delegates many of whom are borderline Libertarian to Libertarian to nominate Rand Paul.  

Non-Libertarian conservatives are split between Rand Paul, Ben Carson and Ted Cruz.  The closed primary convention will surely kill Ben Carson's and Ted Cruz's chances here in Michigan. 

So which direction should the Michigan Republican party choose?  An open primary or closed?