Double blades are the best thing that has happened to my bussiness since i started the company....ive been using them for 4 seasons on every machine i have ..
pros- increased air-flo in deck resulting in smother more even cut....stripes twice a dark compared to single blade...discharge is finer, spreads more evenly and goes farther.
cons- pain in the but to keep up with sharpening 4-6 blades per mower.....can rob HP is you are under powered to begine with.
As far as blade type goes it really all depends on the season....in the
spring-dual high lifts
Summer-high lift bottom Gator on top
high lift blades give you a little more airflo inside the deck and ussually reust in a more even discharge pattern. thats why i use them in the spring when the grass is tall.
mulching blade do exactly what they are called....they are good for leaves, dry grass and great for field mowing. in wet or moist grass they tend to make the grass clump up from the test i have done at least....so i would stay away from ussing them for spring clean-ups and spring cutting.
Check out the Meg-Mo System - They are a sponsor at the top of the page - click on their banner. The blades are disc type with 4 swinging end blades, and basically mow like doubles, except maybe better.