If you haven’t tried Battlesworn yet, get on with it. Particularly if you've got youngsters, as its innovative use of negotiation has got to be an excellent learning tool.
This is a guts reaction to the rules and a simple adaptation. I haven’t tried this so please feel free to shoot me down in flames and please do better!
My suggestion is that the spells are renamed as two distinctions, the device,weapon and the inherent ability.
Warmage is replaced by Specialist (or Mechanic, Engineer, Fabricator, Weaponsmith) as such may retrieve a device from a fallen enemy for future study, but may not use.
Sorcerer is replaced by Master Specialist (or above). I'd suggest a limitation of 3 spells/abilities. A Master can pick up and use an enemy weapon, dice roll for complexity. Looking down the wrong end and pulling trigger is not an effective method of examination.
Limits on types should be negotiated, as it will be easy to have a strong party of a few, against a rabble controlled by a very powerful master. One side may employ standard magic as per normal, with the normal limitations per side.
Now the tricky part. As a device can be copied, a soldier may be equipped with same, effectively making its cost “2”. This is opposed to the standard fighter or shooter who still costs 1.
This is my take on the 2003 film version of League of Extraordinary Gentlemen.
Please note that the main participants will rarely be together and have a supporting cast of sailors and mercenaries.
Each of the following cost 2
Quartermain Leader Sniper
Cpt Nemo Fighter Specialist
Rodney Skinner, invisible man, As summon dread wraith or Rogue Psychic Armour
Mrs Harker Flyer Vampirism
Sawyer Fighter Fireball (fast shooting match rifle)
Mr Hide Brute Fireball
Dorian Gray Fighter Vampirism
Fantom Tank Leader Specialist @ 3
Dante Tank @ 1
Armoured soldier, Tank Fireball (weapon) @ 2