Maybe it’s just me, but I would be more concerned about the door size than the shed size. Most LT1000 units have a 42” cutting deck, so with the discharge chute attached, you need a door of 48” if you want easy entry and exit. Second, look at the door height, as from experience I learned that not having a high enough door means a sore head. Personally I would recommend going 12’ X 12’ platform, which will give you extra storage area down the road. You could go 8’ X 8’, but this would cut storage area and making roof design more difficult. Just my thoughts, might not be worth the time to read it. Remember, your better half will see it as a place to store their garden stuff.