Low-mids is what will give you definition and presence in the mix. Anywhere from 250Hz to 500Hz or 550hz will do the trick. You don't need to boost it a bunch. With a 15db +/- on my Eden amps and my DNA-800, I run the boost up to about 1:30 with my passive Jazz Bass. If you boost it too much, your sound will honk at you. Then just turn it down slowly until it stops honking.
Give that a try. Works for me!
Here's an iPhone video from about 3 years ago where we are playing Somebody to Love by the Jefferson Airplane. It was the second time we played the song and the recording is just OK. But you have no trouble hearing me. I'm running through my Eden WT500/800 amp which puts out 400-watts rms per channel into 4Ω or bridges to 800-watts rms into 8Ω. I'm pushing two Eden EX-112 4Ω cabs, each plugged into its own power channel.
I ran everything flat except for the low mids. I selected ~250Hz and ran the boost up to 1:30. I'm playing in a group with a loud drummer, keys, two guitar players and me. I'm not burying everybody at all, but I have a nice presence in the mix and you can hear every note I'm playing: