I disagree with your analyses. Most of the 30% who support Rudy aren’t supporting him because he’s pro-abortion. The vast majority of his supporters fall into 2 groups. A) Those who believe the skillfully crafted myth about the wonderful job he did as mayor and the equally mythical belief that he was some kind of hero on 9-11. B) Those who mistakenly believe he’s the only Republican running who can beat Hillary or Obama.
Almost all of these people also fall into the broader group that will vote for ANYBODY the Republicans nominate. There’s no need to worry about that group’s vote. They aren’t going to leave over abortion or anything else. You can count their votes right now.
The people politicians have to make happy are the people who are deeply interested in their particular issues, and who have what the Ford Republicans said the Reagan Republicans had, a “rule or ruin attitude”. These voters will stay home or vote third party if they aren’t satisfied.
The party can’t win if they nominate someone who is as liberal as Rudy. There just aren’t enough “anybody but a Democrat” voters to pull it off. The ONLY chance Republicans have of winning is to nominate a conservative.
The ONLY way for someone with Hillary's polarizing personality and high negatives to POSSIBLY win--is to nominate a liberal who SPLITS the Republican Party wide open while demoralizing the base. No one does that better than Giuliani. No one.