I use a mulching mower for the grass and have NEVER picked up grass with a mower. You're throwing away a lot of nutrients by taking up the grass.
When I took care of 5 acres of lawn for the church in NJ, I mowed it with a 4' Scag and chopped up the leaves from numerous oak trees with it, too. When the leaves got really thick, I'd run the Scag discharging inward until it about choked down, then reverse for a round or 2 and then go back to discharging inward. Some silly folks would rake some of the leaves into piles. I'd just charge into a pile with the Scag and chop them up.
At one time, they had a Sears tractor mower, with a big motor mounted behind the seat that sucked from the mower deck and discharged into a covered cart behind. WHAT A BUNCH OF NOISE! I put up with it for about 5 minutes one day. This was before I took over and insisted them buy the Scag and junk the rest.
Ralph