Nick,
I've done a few decals in the past, so I'm certainly not an expert. The paper choices you've linked should work just fine. I have an older HP inkjet printer and once I printed the decals and let them fully dry, I sprayed Testor's Decal Bonder (#9200) to seal the ink/paper. I'd really like to find a local source for decal paper that can be used on a color laser printer...I've got a really nice HP I want to use.
The first choice you linked, in their ad, tells you that they recommend using the Microscale Liquid Decal Film (their #127). I'm pretty sure it's more or less the same thing.
If you get the Experts-Choice paper, I'd get the Microscale too. A friend did up a partial sheet for me using an ALPS printer and he recommended the Microscale stuff too.
Mike