Thanks all - yep, since it looks like the Pro-Pride is what it is, the tires will be next. Curse of the Internet....spent LOTS of time on various forums/sites looking for best tires to tow with, and didn't get anything solid for specifics, except for the Michelins....and now of course come the opinions that they are not the best (expressed by others, too!) Not that I am arguing against those thoughts, it was just tough to sort out what the alternatives should have been.
Get to repeat the drive test after the 4th, we'll see what airing up will do. JBarca sums that topic up well....