Nurture Program when someone downloads content, but needs to be removed and added to another nurture program if fill out a trial form

Maybe I'm overthinking this, but I've been working on implementing this nurture-type program and I find myself creating 30+ trigger campaigns to do it. Is there a better way??

Here's the flow:

1. Lead downloads any of our 3 eBooks (A, B, or C)
2. Lead is pulled into a Content Downloaded trigger campaign that
   1. waits 1 week
   2. sends email 1
   3. waits 3 weeks
   4. sends email 2
   5. waits 3 weeks
   6. sends email 3 IF they did not already download eBook B
      1. if they downloaded eBook B, they move on to email 3 where they are prompted to download eBook C
         1. if they already downloaded eBook C, they need to move on to email 4
   7. The above basically repeats for the remaining emails in the program

Throughout this flow, if the lead ends up filling out a Trial form, lead needs to be removed from the Content Downloaded trigger campaign and placed in the Trial Nurture trigger campaign

1. Lead is supposed to pick up where they left off of in the previous nurture (example, if I got email 3 and filled out the Trial form, I need to get email 4 of the Trial form nurture trigger campaign)

Is there a way for me to do this without 30+ trigger campaigns? I tried using an engagement program with streams, but I can't figure out how to build in all the "ifs".

Thanks in advanced for any ideas I get!!

Danielle