I had things planned out that (since I can't level worth heck) I would use SC I already had to get the boosts, under the excuse that it'll be like spending for a normal unit, just a bit more expensive.

Then I messed up one map because I forgot I swapped out my healers for that one challenge that requires no healers. Then I looked up and realized I wouldn't get enough stamina or charisma in time.

...Ugh, people weren't kidding about being set back months when you use silver units as fodder. Well at least I learned my lesson.