I agree about the base. I typically use the stereo output and a two channel amp. Then I can eq the base and the treble separately, and set the volume different. The only problem I have with that approach is where the split for the two channels occurs. It’s too high.
Getting even sound but cutting the base down enough is tricky. I also use a Fishman Pro EQ and find it works fairly well.
What may help is if you read up on wire strung harp technique. I have Ann Heymann’s Secrets Of The Gaelic Harp. I use some of the dampening technique she teaches in that book in the base. It works rather well.
I also arrange the base parts to make them simple, and depending on the melody line I sometimes use “Power Chords”. I figured if they work with overdriven guitar to keep it from becoming an atonal mess it would work with the excessive sustain of the base. It helps.