Bean is the man to talk to. I trust him very much. Brian or Cale from BTS have all kinds of good info as well. Oh yah, and Swamps and DI and WOP and BWD and _______(you input name here)
With the D66 stage 2 single shots are the largest you should go. Stock injectors will work but with the AB injectors they will be maxed out from the start.
With the H2E I would get at least stage 1 single shots however I would lean towards hybrid injectors. Stock injectors will work but with the AB injectors they will be maxed out from the start.
With a modded H2E, this is what I run, I would say at least a stage 2. B codes or hybrids are going to be the ticket. B codes are what I run and I have all kinds of fuel and no turbo lag.
With a ball buster I would go with stage 1 or 2 single shot injectors. Depends on what kind of power you want to make. Single shots give good power and you get better fuel economy with single shots.
Towing is what I do the most. But with my set up I tow, sled pull and drag race as well it is my daily driver. My truck makes 350hp/750tq in tow mode and 500+hp/1101tq in my race tune.