I’ve got the VP112. It’s the home model of chamber sealer, and I love it. Single seal bar (which means that I have to seal twice most times).
This isn’t scientific but it seems that the drybags need a longer seal time to get the right seal. For a regular vacuum bag I use a setting of 6. For a drybag I use a setting of 9. I get great seal quality.
I found that at 6, the drybags didn’t really seal. And 9 worked. I didn’t try 7 or 8. And of course there’s no way to correlate what I got with my 112 to what you get with your 215. I think you get the better vacuum pull. I get something that works on the countertop!