you can use 100% VG, you'll still have to punch them though, i highly recommend going to your local hardware store and grabbing a 1/4" self tapping saddle valve to punch them, as they cost around $6 and are much easier/safer than using a hammer and a nail...you can also find them online for about $4, here's a link:
Anderson Metal 59199-04 Self-Tap Saddle Valve 1/4"
that should give you an idea of what they look like as well as an online option to buy if you so choose...if you really want a tank and you are outraged by the idea of HAVING to punch cartos, the only real option is the vivi nova, as i find the pre punched cartos aren't enough even with 100% pg