I recently finished collating the second quarto with my transcription of the first quarto. I knew going into it that the differences would be relatively minor, and based on the principle that a change is transmission is a breeding ground for errors, I think that most of the differences don't really qualify as "improvements." Most of the time, if Q2 has something different from Q1, it's worthy of a foot note, some of the time it might be useful to know there is another option available, and maybe one of these differences will actually find its way into one of the final products.
Still, the exercise was extremely valuable for one simple reason: I made a lot of my own errors when transcribing Q1 into a digital file. The differences between Q1 and Q2 were so minute that the only way I would be able to catch them was to go line by line, and every time I encountered a discrepancy between Q2 and my transcription, I turned back to Q1. Most of the time these discrepancies were the result of sloppy work on my part, but being able to see that helped me realize something that I hadn't thought of before: transcribing and collating quartos requires a lot of focus.
When I was making my initial transcription of Q1, I pushed myself through bleary eyes and headaches to get the thing finished as quickly as possible. That was a mistake, and seeing the sheer number of mistakes I made as a result of taking that approach helped me realized that working that way is extremely unproductive. What good is a collation if you can't rely on the copy you're collating against? So I took the Q2 collation much more slowly than I did the Q1 transcription, which is one of the reasons why I only recently finished.
The reward for finishing this collation will be collating what I have now with Q3. Experience tells me that is going to take a while. I almost said it would take even longer, but making the decision to use Q1 as my copy text means I'm not obliged to check every single discrepancy against Q1 and Q2; in fact, that would be a waste of time; I've already noted the differences between Q2 and my copy text. Now I need to see how Q3 informs my copy text, which will of necessity include Q2, as that is now a part of the text I'm working from.
The more I think about it, the more I realize that I'm even more interested in collating my text laterally against the other Q1s out there in the world (besides the copy I got off of EEBO). Hmm.... because I and obsessive compulsive and like pain, I think I might have to look into that.
Why am I going out of my way to make my life harder, anyway? Sheesh.