Can't help on #1, but on #2, our seal wasn't great either from day one. I cut pool noodles to fit under the bottom, notching out around the slide tracks. They were a very snug fit. It just became normal routine for us to put these in there, as it was the only way to really keep out the bugs in the summer, and cold draft in the winter.
John and Rebecca Dickson
Emma-7 / Little John-5 / Iva-1
Full Timing Again, Rev B
2013 Ford F-350 Lariat CC LB PSD
2015 SOB TT - With OC's Awning Poles (#8)
At least in Heaven, RVs will be perfect, and I won't have to keep fixing them.