I have an 8x12 shanty and have hauled shanty's up to 8x16 with no problems when they where lined with uhmw. I have tried moving smaller shacks with make shift bed liner runners ext and had a hard time moving them. DO NOT SKIMP ON YOUR SKIS! Two people can push my 8X12 by hand in the right conditions.
Here is what I have learned:
1.) Make your skis 8'' high, so you will not plow as much snow if hauling it with a snow machine.
2.) Use 8'' wide and 1/4'' umhw on the bottom of skis, you can over lap the edges of your skis an 1'' to cut down on the size/weight of your ski. This will give you great flotation and more umhw surface area.
3.) Countersink the screws in the umhw.
4.) Curve both ends of your skis and run the umhw to the top.
5.) weld a good, stout hitch and attach it to the top of the ski with brackets, and you will avoid plowing snow and causing any drag. Make your ski 3' longer than your shack, so you will have 18'' of "meat" to attach your hitch. You can also cut an 1'' strip of umhw and use it as a runner, so your shack will track your sled and not sway.
I have used 5/8" threaded road and drilled down through the floor of the shack and through the ski and made up with washers and nut, flipped shack over and covered with umhw. Works great, there is no need for braces under shack along skis, so there is no drag when hauling. Timberlock screws work good also.
A lot of this will depend on if you are using a snow machine to haul your shack, or if you can drive your truck out and drop it off/pick it up. I haul my shanty 30-50 miles a season and can't get a truck on the lake, so light weight and skis are crucial. I would rather drink beer and fish than drink beer and work on moving my shack. Good luck and hope some of this helps