If you have 8 acres of tops to crawl around in and to clean up, get yourself a light pro class saw.
How many trees were cut on the 8 acres? We did 10 acres a couple of years ago, but only let them take the 70 older trees we wanted to get rid of.
If there's a lot of wood to cut up, and it's all tops, I think a 372XP or PS-7900 with a 18-20" bar, and a 260/346NE/5100S with a 12-14" would get the job done in a hurry.