Controlling Drill Motor Speed - Universal Motor

I've found various useful articles here, so it was time to become a member, so thanks in advance for any help!

I'm currently working on a project to use a standard drill as a mixer. I want to mount the drill to a mixer stand, but I would like to be able to control the speed with a knob vs holding the trigger halfway for 10 minutes at a time.

My understanding is that drills typically use a brushed type universal motor that accepts AC or DC, so my question would be how do I control the speed?

I believe they use use pulse width modulators or triacs for a lot of these triggers, but would it be possible to just use a DC drive like a minerak or KB to control it, set at 90v dc? or is there a better alternative keeping the power AC using another triac or PWM

Note its a 110v drill, the attached picture is the trigger I pulled out of it

Thanks!
Scott