suggestions

Hello I need to dev a small app and I can think of a couple different ways to handle it but not sure the best way. I need to register those who come to our site that want to download .pdf's. They will fill out some information before I redirect to the pdf. I'm thinking the best way to handle this is sessions, but is it appropriate to store all of the users info - so that if he downloads 2 items - I can re-populate the fields so he doesnt have to? So if they click on an additional pdf I'll need to somehow check for the session and re-populate 11 fields, and they will only have to fill in one field at that time. Or would cookies be better ? I need to store probably 11 different form variables. Also - would you store the variables in an array in the session? This seems neat and tidy... Hope this is clear. Any advice/guidance/sample scripts would be appreciated. Thanks