So, I was curious about the Dalvik heap size mod. My phone is not very modified, it is rooted and I removed most of the crap apps like Blockbuster etc. that came with it.
I set it the heap size, and rebooted the phone. Waited 3 minutes to allow it to come to a stable state, and ran Quadrant 6 times in a row. I did not disable or modify anything to improve my scores, it is just as I carry the phone every day. I had a strong 3G connection during this time so any polling done by widgets or whatever should finish quickly and not affect a lot of the tests. These are not the be-all, end-all of tests, I am just reporting my curiosity in a somewhat controlled way.
Given the couple low values on the first round and the incredible consistency of further tests, I'd say we aren't helping our quadrant scores. From the initial comments in this thread it looks like it just gives a larger memory space for individual apps, so I think I'm going to leave it on 40m for a little while and see if I notice a difference, especially in things like the browser where I frequently open many tabs.