long bed to short bed

ok so im new here and a wee bit new to welding but i have read alot and will soon have my hand on a welder and start practicing the trade optimally i want to be able to tig weld either an air bag set up or just do the short bed conversion but before that i just want to gather up info as to how the best way to go about this would be... now i know that it will be a butt weld at a slant that i will do for the short bed conversion on the frame side but i am still curious as to how i would do the bed portion of the truck i figure it would be to just cut it and bring it in 2 feet which would make it a true 6' short bed.. anyways i know its not a beginners project and i dont plan on doing it for at least a few months but its always good to get the info on the brain so i know what methods to start practicing... thanks for any info.

Most longbeds have to be shortened both front and rear to fit a shortened frame. A slant cut on the frame will work, but it would be better to cut straight down, half way, then horizontally for a foot or so, then straight down again.