I am lactose tolerant as well and have been training for quite awhile now. I use whey protein as my primary protein supplement.
1. Avoid Whey Protein Concentrate. I found even a label that said "low lactose levels" was enough for me to break out. I found most WPC to have some lactose in them.
2. Whey Protein Isolate works the best for me. I did notice some intolerance when I was taking in WPI with some carbs (like Isopure WPI or Isopure Low Carb) but when taking Isopure Zero Carb I found I had no intolerance. This is my 2nd month using the stuff and I haven't had any lactose based allergic reactions.
Bottom line as my recommendation for you. WPI and scrutinize the label for the words "Lactose Free".
Regards,
CT