I think the most important part is making sure the entire band is cohesive in their performance and overall sound and can do the covers "justice" (LOL, let's not get TOO serious here!). I think ROI is a relevant question from many vantage points including time to learn, time to tweak the tones, investment in the appropriate gear, how long will it take me to get from patch #1 to patch#2 with all appropriate tonal changes, mid-song or mid-set, etc... Personally, I think a lot of these things from a well seasoned gigging musician becomes simple common sense after a while. I played in a two guitar outfit for a while and every so often one of us would dig slightly deeper to really nail a certain part or tone/effect of a particular song and it was cool. Healthy competition. Hell, I probably got the gig because I learned the three separate guitar parts in King's of Leon "Sex on Fire" and at audition simply asked the current guitarist which part he wanted to play the most... I also worked with another band with two guitarists and the other guy seemed to REALLY spend time dialing close to album tones/FX. He was a really nice guy and definitely devoted way more time and effort to learning the parts and dialing the tones then I did; the problem was he simply wasn't good enough to perform the parts at tempo, cleanly and correctly in a live band setting. Take The Killer's "Mr. Brightside". That has a really cool and interesting intro part, I think in band #1 mentioned above the guy actually tuned down one string to make it easier to play? In band #2 the guy learned it and dialed in a really close tone, albeit super bright and nasty sounding on his Zoom G5. But every single time it came to rehearse the tune super flubbed... as in, hold on, let me start over, etc... Guess what? I'm not letting you do that **** at a freaking gig! Same thing with Message in a Bottle; I just do a simple dotted 1/8th delay with some chorus. It sounds loud, clear and works perfectly. This guy had the compression, amp model, flanging, everything totally dialed in. BUT, he couldn't play it to speed and definitely couldn't sing over top of it! I've been playing that riff for 30 years, I'm not gonna NOT play that **** the right way. So, performance of the part is crucial. Perfect exemplary matching tones, distant second IMHO. And "dimed Dual Rec" on every part of every cover (unless you are doing super heavy stuff 100%) is just ****** and inappropriate tone which is the mark of inexperience or just not talented (or just deaf).