…The analysis, based on exit polls conducted by Voter Research & Surveys (VRS) for the major news organizations, indicated that in Perot's absence, only Ohio would have have shifted from the Clinton column to the Bush column. This would still have left Clinton with a healthy 349-to-189 majority in the electoral college.
And even in Ohio, the hypothetical Bush "margin" without Perot in the race was so small that given the normal margin of error in polls, the state still might have stuck with Clinton absent the Texas billionaire."
https://www.washingtonpost.com/archive/politics/1992/11/08/perot-seen-not-affecting-vote-outcome/27500538-cee8-4f4f-8e7f-f3ee9f2325d1/?utm_term=.6790ed3f7675
Also, there is this:
“The Man Who Supposedly Cost George H. W. Bush the Presidency”
http://www.pollingreport.com/hibbitts1202.htm
This article delves into the pre-election polling, as Perot entered, un-entered, and re-entered the race.