Good day!
Just thought I'd share my experience...
First, bass amp models sound much better after tweaking. Anything to "tighten up" the sound, like the sag and mic distance. Second, two paths sound better than one; flattens up your tone. Third, dialing in a tone as close to live volume through my home pa gets me closest to what it will sound like live through the fronts, but headphones get you close. Usually I am asked to turn down the lows a bit, if anything. I went live for a show with a loud drummer (godsmack tribute) and ONLY a Peavey DM115 (no back line). I managed, but it didn't cut it. Not loud enough, and no subtleties came through. Guitar players seem to have no trouble with the same set up, but most sound guys don't seem to fully understand modelers, and that we are trying to avoid being at their mercy for monitor volume. This is less of an issue in larger clubs with larger PAs and good sound guys.
Best sound I get now is backlining with my mark bass tube 800 through a single 4x10. I use the helix in front of it, replacing my tried and true, and hard to beat, ME 50B, for volume, tuner, compressor, effects. Honestly, I haven't figured out how to make it sound as crisp and clean as the me-50b, but it's close. Now here's the thing, I run a completely different rig to the front of house. Usually the Hartke with the 8x10. Lots of compliments, and I can hear over the rest of band.
I have not yet found a monitor that is loud enough for me to go without the back line. I'm about to get a QSC power amp and Yamaha 12 inch monitors. I'm hoping that's going to work out. As much as I would like to walk in with just a combo amp, my situation requires serious volume, and I can't only bring one amp and hope it doesn't blow.
Lastly, my mark rig with the ME 50B, is very portable, and sounds better than most rigs to my ear. I bring an extra head with me just in case and I actually run two 4 by 10s. But I don't get all the bells and whistles I get with the helix. That's where I'm at! I didn't see anyone else posting about playing bass through the helix to the extent that I'm trying to. Comments and suggestions are welcome!