i have a rack'em 4.4 cubic foot grass catcher for my metros it works really well. they do make an extension for it that would increase it by 4.3 cubic feet which would be good for leaf season i think but i have never used the extension not sure how cumbersome it would be to deal with.
mine is older and came without the easy lift handles but is the same catcher
i have the ultra vac for my lazer that works great. i dont know much about the trac vac looks like they are made for tractors and ztrs not sure how a belt drive walkbehind would do that.