Here´s a nice demo of a Mesa California Tweed amp
https://www.youtube.com/watch?v=ZtjGijMx2-M
it is very helpful to achieve a similar sound from your modeled IK gear.
Keep in mind to push the input slider and boost with the Slash booster if necessary to get the gain structure (thanx to user Matthias Mueller).
Please post other gear demos from original gear to compare with the modeled stuff.
And here´s a DR.Z Maz 18 JR (at 22:25)
https://www.youtube.com/watch?v=-zZU3RdslTU