Definitely, without a doubt, make it a four sided shed with two doors that open wide enough to get the tractor through. It's crucial to keep the rodents out, they love to make nests in/ near the air filter, engine places, and chew wires. It's also crucial to keep your best equipment as dry as possible. That includes a floor, a very heavy floor, in case your description didn't include one, with a lot of support under it. Better to overdo than undero. A
concrete pad would be good, since that would keep the rodents out as well. It's also great for cleaning out mud that comes in on the tires. You want to be able to lock everything up.
Don't skimp on size. because you will need room to walk around the tractor without running into the mower., and have room at the door to bring the mower out without taking the tractor out, so it
should be deeper than you think. It's also wise to plan on extra space for future equipment, even if it is just smaller things like a chainsaw or a string trimmer. Not making it big enough will mean you may need a second shed, which ends up being more expensive than a larger original shed. You'll want to put extra machine parts, oil, tarps, leftover building material, and tools that could rust or rot if left outside, shelves for paint and spray cans, .
If you are going to build it, (as opposed to buying a shed kit) it is most efficient to make the size in multiples of the size of a standard piece of plywood, the US that 4 feet by 8 feet. If you make the walls 8 feet tall, like the size of the plywood, you can put in overhead storage. You'll need to walk into it easily without bending over anyway, and using the whole piece of plywood gives you that extra space in the ceiling area as well.
Buy the best siding you can afford, it will last much, much longer and the rodents can't chew through it.
Try not to make it too high off the ground on the door side, so any ramps that get the tractor inside are not too steep.
I installed vents that can open and close to control moisture. I paint a wooden floor to keep it from soaking in stains, but I don't paint the inside of the walls so they will absorb moisture.
Sheds in the sun may be hot during the day, but that's passive
solar heat, and they will dry out and have less mold in them. You don't want a shed where a lower limb of a large tree might drag against the roof and wear out the roofing material faster.
I don't have windows in mine, because the vents do a good job on air flow, and with two doors open there's enough light to see.
I like to use opaque stain on the exterior, it lasts longer in direct sun than paint does. I just painted over some stain I put on one shed 15 years ago, it is in the direct sun and lots of wind. The only reason I restained it was because I wanted to change the color. The original stain was still in great shape.
Having to re-do things even 10 years down the line is expensive. Sheds never get cheaper, nor the material to make them, so make it an investment that will last for decades and not give you a moment's worry during bad storms.
