My general rule of thumb is the politician has to vote the conservative position at least 80% of the time to be considered a "reliable" conservative (the ACU uses this standard too, but we shouldn't just look at the ACU score alone to determine if they're 80% conservative), and someone I'd consider supporting in the primary election. To be considered at least acceptable in the general election, they have to vote conservative at least 60% of the time (a Republican who votes conservative 60% of the time would be a moderate "hold your nose" squish). I may even hold my nose and elect someone who votes conservative 51% of the time, but probably only if their RAT opponent is pure evil and MUST be defeated. But if the Republican is voting conservative like 30-40% or less, they should just quite the farce of running as a "Republican" and join the RAT party.
There are handful of exceptions to this rule -- for example, both Ray LaHood and Peter King vote conservative over 60% of the time and I wouldn't support them under any circumstances. But those are generally very special circumstances, for example LaHood is clearly working to destroy the GOP from within and elect Democrats, and Peter King is clearly a Clinton yes-man, and a terrorist sympathizer to boot. (for more reasons than just his impeachment vote)
I don't make exceptions or give them a break based on their geographic region. A Republican in South Carolina and a Republican in New York both have to get over 80% conservative record to be one of the good guys in my mind. (Also someone who has spent YEARS voting liberal and decides to morph into a conservative overnight to get nominated for an office is not going to get my support. I look at their lifetime records). The GOP is a national party and ought to have a national unified message, and I don't think running as Democrat-lite makes candidates more "Electable" in states with larger Democrat populations. It's going to be difficult for a Republican to win in Rhode Island, regardless of whether they are a RINO or a conservative.
What some people fail to separate is Republican from Conservative. I’m a Conservative, and have no use for Republicans that support a liberal/left agenda. There’s no need for two parties pushing a leftist agenda, and it is a recipe for death for the GOP. If you’re a liberal in the GOP, the question is “Why are you a Republican ?” Their sole purpose is to undermine and destroy it as a vehicle for Conservatism.