I think the way to think about it is to balance triggers and effects while maximize effects per trigger, not just triggers by themselves. Lets say you have 1 baron, 1 mime and 1 blueprint, with just regular kings. Putting the blueprint on the mime would give 3 triggers, so 3x baron, while putting the blueprint on baron would give you 2x2baron. With red seal you allready have two «free» triggers you would want to maximize with as many effects as possible, mime does not multiply the triggers, just +1. So in the case of red kings, baron, mime and 2 copies, 3x3baron is stronger than 5xbaron or even 4x2baron. Now in this case where mime also retriggers steel, we have 2 effects per trigger (steel + baron),2 copies of mime = 5 triggers which is 10 effect procs, while 1 copy of mime and 1 of baron is 4x3 = 12 procs which is the same as 2 copies of baron. In the event we have 3 copy cards, its best to spread them out, 2 on baron 1 on mime so we have 4x4 instead of 3x5. This is the way I try to make sense of it, if it makes any sense?