1) I am amassing a lot of two-star and three-star units hitting the maximum level of 20. Are they of any use or should I just feed them for training up my Valiant (Freya) and two 4-star units for now? It seems there is no difference in the points earned from feeding a lvl 1 to feeding a lvl 20.
2) I started playing yesterday evening and am now halfway across the second map. I am following the general advice of "amass 450 gems and roll for Heroes". Currently I am facing a gold shortage as my two 4-stars and my Valiant keep hitting max levels and feeding them units to Train/Upgrade. Am i on the right track?