Hi Erika,
I’m sure there is someone out there who has a simpler and more informative answer for you. But here’s my 2 cents. I’ve found it’s challenging to find good pre-made duplex stocks. I usually end up making it myself to get exactly what we want. Business cards are great because they’re small and you don’t have to do to much handwork. I’ve experimented with dozens of adhesives and the trick is to get an adhesive that is dry enough to not cause drag on the cutter knife (too much drag=crooked cuts) and that won’t warp the paper. 3M has a great product that is very expensive and I use it whenever the budget allows. The cheapest most labor intensive method I’ve found is 2 coats of rubber cement (1 very thin coat on each side, let dry, then stick together). Another cheap way to go is to find an Avery label stock and stick it to museum board or some other thick stock. Let me know if you have more questions. I could talk all day about adhesives. 🙂
Last, I will leave you with, I think, an invaluable tip that my cutter maintenance guy passed on to me. Spray your blade with a low friction dry lube made with PTFE (I got it from Home Depot) and let it cure overnight. This lasts through a few dozen cuts (depending on the stickiness of your adhesive).