I'd like to add my $.02 I play regularly at a 2000 seat venue covering a variety of guitar tones and styles of music. I have the dream rig and even though I have good majority of the guitars my JTV models I usually fall back on the JTV for convenience and consistency. I vary between going direct out and using a DT-25 head and cabinet. I use wireless in-ears and usually a wireless pack for the JTV (wish Line 6 would integrate their wireless with the functionality of the VDI cable..but that' another topic.)
One person mention adjusting the patches to sound good in the in-ears and I disagree wholeheartedly. You want your patches to sound good throught the FOH. The in-ears mix and sound is what it is, work with whomever does your monitor mix to make that more pleasing but don't tweak your patches for the monitor mix. This also may be painfully obvious but make sure you have the HD output set to Direct Out if going direct or it will sound like you know what.
I go through a 4 step process to create new patches. First using HD Edit and my PC monitor speakers (I have decent ones not uber expesive ones) if I have a patch I know is good and close I start with that otherwise I look up the artist and their rig and start building from there. When I get in the ball park I use the headphone out to decent Sennheiser HD 280 pro headphones and dial it in more. Next I'll hook my rig up to a EV LIve X 12" powered speaker and make adjustments at gig volume. I cut the highs, lows, and presence to a finite EQ band that my guitar will cut through the mix and not muddy up the bass, keys and vocals and not have the brittle harsh highs you get especially when using distorted or overdriven guitar tones. A FOH FRFR system is going to accentuate a much broader EQ band of your gutar patches than a normal guitar amp that is generally mid-focused. Finally, at sound check I'll work with the FOH guy to fine tune anything else. The unit is very easy to make adjustments on the fly once you get over the learning curve. I may use 4 patches in a gig but I have everything mapped out to the F1~F4 with many switches turning on and off multiple effects. I use the FX loop for clean boost and noise gate on almost all my patches as well.
That being said, if I had to play multiple venues I'd focus more on my DT-25 and mic'd cabinet set up. I have separate common patches for each setup adjusted accordingly. You can pick up this amp used for about the same as the others you mentioned and I strongly recommend it now especially with the new firmware that allows you to tweak the default settings of the amp itselt in standalone mode it so worth waiting and saving a few more dollars to get it. You'll be kicking yourself later if you don't.
I go through the same steps but rather than adjust at gig level through the EV I use the DT-25 and 1x12. I acutally use a 1x12 Blackheart cabinet with Eminence speaker at the venue so I don't have to shlep mine. IMO the DT-50 is too much. I have a DT-50 head as well and it's too loud (not to mention heavy) I would rather have more tube saturation by cranking up the DT-25 to about 2 o'clock than the DT-50 at between 9-10 o'clock for the same volume. If I had to play all clean I probably would use the DT-50 because it has more headroom but I don't so it is collecting dust right now.
I was the one who said i set up patches through the in-ears. I do that because we control our own in-ear mix on stage. It never changes, where as the FOH does. The in-ears I use don't change either. I know my in-ears like I do my studio monitors, so I can mix and set up sounds pretty well. It's not like I don't check them out through a PA sometimes though. I still have to make sure they transition to other sources well.
So, the FOH sound guys at each venue always get the same signals from everyone in the band, save for the drummer (everything's digital except for drums). Then, they can mix it according to their specific venue.