You've been around long enough and posting enough that I'm not worried about sharing svn access with you. If you PM me the email address that you'd like to have associated with that, I can get you set up and have some emails with how to download things, etc. Are you on windows? It's fine if not, but it's more complicated and requires a bit more from you in terms of custom setup to pull stuff.
Given the nature of svn, it's not like you can break anything permanently, so the main thing that we ask is trying to stick to code conventions as much as possible, but even I've messed up whitespace a fair bit from time to time because of some visual studio settings getting reset and me not noticing, etc. So stuff happens, it's no big thing. And especially if you're just in the xml at the moment, that's the easiest part to change and really is less of a big deal.
But my goal is generally to make it so that folks have as few barriers as possible to being able to contribute even if it's just a bit of stuff; I agree that as a player, having to search around for mods tends to just Not Happen most of the time, and if someone wants to run off with the source code they can pretty much just decompile it anyway. So it's not something that should create a sense of obligation for you, where you then NEED to contribute a certain amount or something just because you have access, I want to make clear. I totally get that you're busy and have a lot else going on.
I'm quite grateful for the enthusiasm in the first place!
Cheers,
Chris