From my own experience as a big flyer, I would add one more thing:
I would not overdo it with the "slowing down". The problem is, that if you get used to constantly flying near the minimum fall rate you are capable of, you will develop a style that you will later have to unlearn, because it is not the most efficient and flexible style of flying, especially if you get into more competitive formation skydiving, such as 4-way or 8-way. Now, some of that may be unavoidable, and there will probably be multiple times, when you have to unlearn some things and update your flying style.
Nevertheless I think it's best if you mostly try to fly somewhere near the middle of your range and, if anything, try to increase your range in BOTH directions--which, as others have pointed out, is best achieved in a tunnel: For example, if you are currently most comfortable flying at 74% speed in the tunnel, but can fly between 72% and 76%: Don't just try to get to 64%. Instead try to increase your range to be able to fly between 68% and 80%, etc.
That way, when you DO fly with really slow fallers, you can match them, but you'll be aware that you are flying on the low end of your speed--rather than just unconsciously adopting an extra-slow flying style.
Ultimately, in teams, the slower fallers will wear weights. The only way the faster fallers should probably adjust to the slower ones is by loosing weight!
...but for beginners, wearing weights is not a good idea, because of canopy loading--so don't ask them to do it...yet!
Suits will definitely help. A little bit of extra fabric between the upper arms and body can greatly help. I got my first RW suit, by talking to Bev from BEV Suits, and 400 jumps later it still works great. tony suits is a bit more expensive and takes much longer to get, but everyone says they are absolutely excellent.
Anyway, just wanted to add that.