I train on 26-5 getting as many 2* and 3* as I can while using any 1* I come across as feeders for those cards and I only will level them up to level 4. On a fresh 5* I used 74 of those units to enhance it to over lv. 60. After that I used quest 36-4 to lv. it up to 100, I get 630 exp from that quest and as a bonus I get 50 ally points, yay! Took me 2 days. From then on that is what I have been doing for all my cards. Works just fine for me. Hope this helps. (^_^)