I would save them for a 3* ascension item deal like “Frozen Treasure” - Warm Cape, Compass, 3* blue trainer for 500g
You need 3* ascension items for 4*+19 heroes since 4* 3.60 heroes can not use emblems.
My first 4*+1 of each class is a classic hero from Legendary training except Wizard Proteus ( see Notes ).
4* Heroes are the backbone on Empires.
I am still trying for 2 more Hansel, Gretel, 1 more Jackal, Falcon, 2 Cheshire Cat and one Captain of the Diamond, so Guardians, Grimforest, and Wonderland summons are on my adgenda ( all together now - 4* are the backbone of Empires).
Personally I get my loot tickets from VIP Pass and “It’s raining loot tickets” deal - gems plus loot tickets.
Fast Lane is too expensive for me. Energy flask you can buy with the gems from “It’s raining loot tickets” and Legendary Training ( RT20 ) gives me enough 3* heroes to level my 4*/ 5* heroes, so I do not need trainers.
(Classic 4* heroes and emblems or Gryphonknight's emblem spending plan EXPOSED)