I think it's really helped me to engineer bass sessions, sure. I seem to have more of an idea of what makes a functional tone by doing that a lot...which definitely translates to mixing too.
My role for the smaller sessions is not unique: I basically just produce myself and direct the session unless someone (the artist or one of his team) is clearly wearing the producer hat. In other words, I find that a lot of time, people are hiring me also so I can make my own choices and produce myself through the overdubs that they need.
And I do think, even in project studio mode, it's important to have a good chain, or at the minimum, some kind of preamp-y/overdrive DI box like a Bass Driver DI, EBS bass pedal preamp thingy, MXR Bass DI, etc.
What I've learned most of all is that it's important to not overcompress, because cheap compressors sound cheap, and people rarely know how to set attack/release/threshold/ratio properly. In the project studio environment, unless you have something good, it's best to stay away from compression (or just have one of those Aguilar comp pedals or something similar that's good just taking a couple of dB off). Also, very important to check for phase and align your DI/amp tracks well (or DI/POD, or DI/Guitar Rig, whatever). Those alignment and phase issues, when left alone, can be a real drag on your tone and impact.
Those are fairly pedestrian tips, but important enough to regurgitate to you here.
Also: I've found great success in having a four-space rack back w/ nice studio gear I can take anywhere. In mine is a nicer M-AUdio interface (ProFire 2626) which I use at home or in lieu of people's crappier interfaces.

In other words, you can just download some drivers, and get going with your own interface. Those are a good value w/ surprising converters for the money. Next is a Distressor, usually for the DI signal, which comes off an Aguilar Tone Hammer on the floor. Then a two-slot API frame containing a 550A EQ and A Designs Pacifica preamp. That's for your amp, or "amp", channel.
Once I'm home or at my studio, I use it there...and at my studio, I have a pre-configured snake all ready to plug into it and all the I/O shows up in the patch bays. That's not cheap stuff, but there are plenty of other great pre/comp/eq chains that can yield great results and be had for much less too.
Hope that might be of some help..
Best,
Justin