Sharing a link below to a blog in which I outlined a cab build for my L3000DT. Couple simple things I think could be of help. One was using old automotive weatherstripping. Most cars have a strip of very nice weatherstripping under the hood by the cowl. Also the weatherstripping seals the trunk is pretty good stuff.
This was better quality stuff then I could find new and the price is right. Getting a tight seal really makes a difference when it is -10 degrees and the wind is blowing.
Another note is cutting nearly through the square tubing then using it to make a pattern. If you go to the site clicking on the pictures will make them larger and it easier to see details.
http://lifeonhighway9.blogspot.com/2011/03/building-tractor-cab.html
This was better quality stuff then I could find new and the price is right. Getting a tight seal really makes a difference when it is -10 degrees and the wind is blowing.
Another note is cutting nearly through the square tubing then using it to make a pattern. If you go to the site clicking on the pictures will make them larger and it easier to see details.
http://lifeonhighway9.blogspot.com/2011/03/building-tractor-cab.html