From stable/straight to overstable:
Old fossil: this disc reminds me of a helicopter when it flies, pushes forward nose down, lands softly to the left. Almost hovering as it comes down which is rare for an overstable mold. The last third of the flight reminds me of a comet, but you have the high speed stabilty off the tee. I throw for straight shots or forehand flip ups that still fade at the end.
Proto Amber: Great hand feel, really enjoy the amber plastic after several rounds of wear. Same HSS, a little more fade than the fossil. This is the perfect Gila stabilty. Can throw it hard without fear of turning over, forward fading finish. Basic straight-with-fade Gila.
New amber: this was the one with the 2 aces in 90 minutes. Definitely can tell the difference between a fresh and beat Gila in terms of stability. I throw this on forehand flexes, which is generally tougher to do with a mid and the Gila does perfectly. I also throw this on more sweeping hyzers. Its like a verdict with less skip, but can handle multiple forehand angles a lot better.
Armor: like you said, most overstable. Mainly use it for longer approaches and around 250 foot spike hyzers (one specific hole with water right). I probably throw this one the least, but thats fine as it will keep its stability.
