What MOD - photographing soccer teams 8 - 20 people

[mal from cessnock]

I have the opportunity again this year to photograph the local soccer(football) club.

I have 2/800 and a 400 AB

Could someone please suggest a modifier that would do the job. I'm thinking PLM (Paul C Buff - Parabolic Light Modifier - range from 46", 64" and 72"? which are a multi ribbed silver lined umbrella) but am unsure as to the size I need. There will be a varying number of players in each team, ranging from juniors with about 8 players through to seniors where the number may be closer to 20.

If the PLMs are considered the way to go should I be using the black back cover accessory to prevent the light going through the mod?

If the PLMs are not the way to go, then what?

I hope to take these outdoors, but if like last year will need to move into a crappy rundown stadium.

Help with MODs would be really helpful.

Cheers, Mal from Cessnock AU