You're welcome.

Why do you want your match rating between 0 and 1? It might be easier to compare an absolute rating. Add all the ratings of the players on the field (from 1 to 10 maybe), multiply it by some sort of "motivation multiplier", "trainer quality multiplier", etc. That way you don't have to worry about the maximum strength a team could possibly have, and it will make tweaking multipliers easier.

for more granularity, do the ratings above for the different sections in the field, or even individual players. Every section or every player has a designated section or player from the opposite team to attack or defend against. For instance
(team 1 defense players ratings times your multipliers from tactics, motivation) weighed against (team 2 attack players times your multiplayers from tactics, motivation) etc. Also calculate how much time per game is spent in each section of the field  (attack, defense, midfield) by taking their ratings into account. All those weights combine into an end score.

Not related to programming (and not knowing much about sports ratings), but have you tried looking up some sports ratings mechanisms?

There is a good explanation including some sort of calculation of the soccer rating system on wikipedia http://en.wikipedia.org/wiki/FIFA_World_Ranking_system_1999-2006

Sorry, haven't really bothered looking further than that, but I bet you can find out more on the official systems used by the sports of your choice (football? soccer? depends where you're from eh?).