I'm not familiar with Salts, as far as I'm aware it's not available in Canada,but I looked it up to see what the flange was made from.
there are 2 things I would recommend trying.
1) I would try to tape the edges down, I would recommend getting a roll of Opsite Flexifix, it's identical to Tegaderm, but cheaper you should be able to order it online, I think Amazon carries. It's pricey for a roll, but the roll I had lasted a year. Not sure if you can get samples of this.
2)Hollister's Adapt Barrier rings #7806, these are incredibly thin and very wide, maybe 1 or so max (they look like
this). In addition to your normal routine, cut a strip off of the ring and apply that to the appliance round the hole for your stoma. This will provide an additional barrier against leaks (possibly prolong for more than 2 days), because it's so thin it shouldn't interfere with the convex bag. Over here they come in packs of 10, I was able to get 7-8 strips off of each ring. You should be able to get samples of this.