I can't answer your hypothetical because I don't have enough facts about the election itself, who is running, is it local, state, federal, etc. etc. This is why most thinking people won't answer hypotheticals and I cannot in this case.
However, I can give you a case in which I would vote for the extremely liberal democrat instead of the "moderate" RINO. It happened in the last presidential election cycle.
Rush Limbaugh figured out that voting for Hillary Clinton in states where votes for John McCain didn't matter to the outcome of the race (like in my state of Virginia IIRC) could put the democratic race into "chaos." In fact, Rush called it "Project Chaos."
Had Sarah Palin not joined the race I was seriously considering doing just as Rush suggested in large part because I had independently come to the same conclusion myself. But I voted for Sarah.
So, my answer in general is that I will choose the best tactics for the battle at hand and not even try to shoehorn myself into a useless, hypothetical ideological straight jacket.
That's fine. I'm not trying to pigeonhole you. I believe it's a legitimate question, yet understand your reluctance to respond..
My own position has evolved since this past presidential election. I was not going to vote for the presidency until Sarah Palin was selected by McCain. That one decision brought me on board. I still punched the box while holding my breath, and with much distaste for the head of the ticket. Obviously, it got me (us) nowhere.
This taught me that making concessions when we follow a ticket is usually little better than not voting at all. As you say, much depends on the candidate, but as a whole, those who qualify as RINOs are generally little different than their Democrat opposites. This is especially true for incumbents. Because of this, I will not be voting for Republicans simply because of their party affiliation. I've drawn my line in the sand. I'm at a stage in life where quality means more than quantity. And I'm through with compromise. If I don't stand for something now, it could be too late tomorrow.
Vote your conscience, I'll vote (or not vote) mine. And mine will be without remorse the day after.