Tracking assets down to individual program in marketo

My company has a drupal set up on the website. Therefore, whenever an asset is downloaded, the drupal form posts information to the marketo form (even though the lead never actually goes to a landing page that hosts the marketo form). Having said that, we have programs grouped by the drupal form the asset is behind. For example, we have a form called "multiple-downloads generic" which has assets ranging from whitepapers, to datasheets, to webcasts. When I do a program report in RCA, I see a LOT of leads come from the "web content" channel. But i want to go a step further and see exactly which TYPE of asset and which EXACT asset is driving the most leads. This is where I am having the most trouble.

I hope to acheive this by breaking the "generic" form down by specific TYPE (have a drupal form for whitepapers, have a drupal form for webcasts, have a drupal form for product downloads). In marketo, I plan on having a program for EACH asset. A different program for whitepaper A, a different program for whtiepaper B, a different one for whitepaper C etc.

In your opinion, is that the best set-up to have? or can this all be managed out of one program, and I'm just not pulling the report right?

anyone having a similar issue? how do you handle it?