Gebrown,
Ignor the negative posts to your questions, most of the people on this forum will pick on anyone who remotely mentions a lifted truck. They are very close minded and will ignor facts and calculations.
They also tend to forget that they make 35" tires in 20" wheel sizes, which I have on my F350, and the side wall is actually shorter than the stock tires were. These are also the same people who also forget your Ram Truck in 2008 had 20" wheels stock with a near 33" diameter tire. So a 35" tire, which physically is actually 34.4 to 34.5 is only 1-1.5" larger in diameter, so less than 6% difference.
Also, these are the same people who don't understand that todays transmissions with Tow haul mode, holds shift points longer, so the gear ratio discussion is thrown out the window with the exception of off the line pulling power.
However, that being said, yes you will be fine with the trailer you have chosen.
In closing, for some reason this forum has a large group of people who just hate it when two major things are combined, Lifted Truck and Toy Hauler. Either one of these seems to start negative comments. I'm not sure if it is the median age of the group, or a mentality issue.
Personally I like this forum for the most part, but the exact posts you received here, is why younger people or people with non mainstream trailers, IE toy haulers, tend not to stick around too long.