I would personally avoid daisy chains.
Here's what I've done in DFP for non-header bidding networks:
1) Enable them and all other networks for price priority
2) Have all networks compete at a rounded increment eCPMs. (For US traffic I use 0.25 increments)
3) Create AdSense passbacks for with custom tracking for each ad network and have them use those for passbacks.
4) All ad placements compete against AdSense in DFP.
I use a spreadsheet set of formulas to determine the following:
1) Network's actually eCPM. (Network Revenue + AdSense Passback Revenue) / DFP reported impressions
2) Floor eCPM set to AdSense Passback Revenue / Network Reported Impressions Passed.
What I've found over many years is that different networks "lose" impressions at varying rates and "lose" passback impressions at varying rates as well. This is where not running your own reports and just relying on network reports and daisy chains will kill your earnings.
Keep in mind that you may need to create different line items for different geo traffic if you get a lot of non-us traffic.