I use the small menu size 5mm (3mm works great too). If I am doing flashcards I just put all the flash cards in and then cut them out after I am done. Sometimes I will then run them through again on their own (not an approved method I don't think, but I've never had a problem). I like the small menu because I can do anything I want size wisefrom 11x11 Doman bits to lots of work flash cards to math flash cards. I just arrange them within the pouch. I get the pouches from lamination king.
https://www.laminationking.com/Thermal-Laminating-Pouches.htmRight now they are having a buy one get one free sale. So for $39.99 you get 200 11.5 by 17.5 inch pouches. That is 20 cents a pouch and you could get 8 2"x 11.5" word cards or 6 flash cards per a pouch. Honestly for us it has been a great deal.