Maybe you can read this article, which was in this topic loaded with useful links.
Limbo : Thank you for the link, but I'd already read that particular article (I actually have the article both printed out and bookmarked) - along with the majority of the articles found in that thread, prior to posting my questions.
The Art of The Mulligan does a fine job of giving a general outline for mulligan strategy, but, aside from U/G Madness, no specifics for Tier 1 decks, which was more along the lines of what I was after.
I must say i still make mulligan mistakes, as i think it is one of the most difficult aspects of magic to date.
BigMac : I absolutely agree, and that's one of the most frustrating aspects for me (other than making blatantly obvious play mistakes that only retarded chimps could rival). Playtesting is constantly underway, and now I'm actually taking notes and saving them... I've got a feeling it's going to take a lot of work than we thought simply to get those decks "down" in order to give an accurate representation when we test our own, and I'm a bit disgusted with myself for allowing myself to slip a little into the "the top decks should be easy to play just because they have Power 9 and are great" mode...
How aggressively you need to mulligan is directly related to which deck you're playing, and which you're playing against. STAX needs to mull aggressively into 3Sphere against combo, but against say, Fish, 1-2 lock pieces of any kind and the mana to cast them is a keeper.
The best thing you can do is establish general guidelines for a deck, and then as you gain experience with the deck, learn how far from those guidelines you can stray. As a general guideline for Long, for instance, keep any hand with a draw spell/tutor and 3 mana. Once you've played the deck enough, you can start factoring other things in, such as the number of lands in your hand vs. waste heavy decks.
In other words, playtest, playtest, playtest.
Necrologia : Thank you for the specifics. They've been written down on the respective notes for each deck. Any advice for a Game One mulligan against an unknown deck? I would assume the lock for STAX, since that's what it was built on?
Thank you for your help, guys. It's much appreciated.