lerp node is the answer:
This guy made more short and straightforward tuts about unreal, so start watching his chanel.
After watching this about lerp, for your material:
- create two 4 value vectors, make them as parameters. Those will be colors used with lerp from tint texture, you can add power node to scale how strong tint texture should be.
- from that lerp you should have nicely tinted tint texture
- multiply that with base texture,
Do something like this:
All nodes on far left are converted to parameters. This way yyou can create instanced material out of this master material. and change parameter values without editin master material.