You'll just have to learn the game I guess and experiment... I don't mean that to be a smartguy response either. I just always felt tactics downloads keep people from learning the game themselves and in the end do them a dis-service.
Read in the Guide the section on tactics if you haven't, download the Guide from the EHM 2005 'Tutorials & Templates' section and it should give you the info to construct your own. Your team will perform best when they are playing to their strengths. That's a basic of all sports really. The game itself has a
lot of pre-set tactics "sets" you can work from to customize until they bring the best results for your team. I'm not sure if people catch that because the wording/execution of it is a bit odd, I know I missed it for months in testing until someone mentioned a problem with it... go to your Tactics screen click on the Tactics button and then down to 'Set to Default' and there is a sub-menu with tactics sets you can use for your team. I know I thought that option was just to rest my tactics to Default, I didn't know it was to set it to default tactics types. This is from within my Whiteout skin so your screen will look different but here's what I mean:
Pick one to start with that best suits your team and see how it works and experiement with some changes to refine it to find what gets your team going. See, I could tell you how I work mine but mine only work for my type of team due to their skills. I try to put together a team with two skill lines and two defensive/tougher lines, and in general my teams are very physical. If you like to put together a speedy technical high-skilled passing team my advice wouldn't work for your team. You have to see what works best for your team.
Tactics that you can download as a "makes every team play like a lineup full of Gretky's" solution are usually taking advantage of game bugs/quirks because there should be no "plug this in and it doesn't matter if you have a good team or not" tactics. EHM is too complex for that, maybe that's why we don't have anything out yet... I think people will always get more out of understanding and figuring out the game instead of figuring out how to get around the game/figuring out how to most fully exploit the game's weaknesses. Yeah, I know that's not a popular sentiment in the world of "OMG! This code gives me 40 Billion Dollars!!!" but that's how I feel.