It really helps mine when I change things up as you mentioned that you do. Sometimes I struggle for ideas for consequences - we try to do natural or at least logical consequences whenever possible.
Mine are a little older than yours, but we use a technique called the FAIR Club. It's something I came up with based on other parents' suggestions on dealing with special needs children, particularly those with attachment issues like mine (although in the first year they all have attachment issues of course!). It's worked pretty well for us. I wrote a series of articles about this technique and the last series has a lot of the consequences we've given for different behaviors.
Here's a link to the first article in the series if you're interested. The format didn't lend itself to this type of information very easily, but I tried. Hope it helps!
How to discipline your difficult child A(without spanking) | eHow.com
Main thing is to remember that especially in these first months these guys are very scared. They've been through some major life changes and need assurance that this is their forever family. They need consistent rules, but also a lot of understanding. The balance is the hard part! I usually find that when they're in the middle of a meltdown they are not able to access the thinking part of their brain, so I reassure them and help them calm down first. Then a little while later, when everyone is calm, I explain to them the consequences of their action (this gives me time to think of something appropriate too!).
Sounds like you are a great Mom!