I have a question for those of you who might have slide toppers. On our main slide we only have 2.5 inches between the slide out flange and the arm of the awning when deploying the awning. Am I going ...
You will be able to mount a slide topper on that slide, but it probably won't be perfectly centered and you will need to consider the overall length of the topper so that you don't run out of mounting adjustment at the end away from the awning arm. The fabric at the awning arm end will probably end up flush with the slide box or slightly inboard. If you are OK with those parameters, then, no problem.