Hi
Keystone engineering is very poor and I don’t think much of Lippert’s either.
Stick with dieselguy he got it correct. The I beam type of constriction requires the I beam to reaming straight up and down to maintain its strength dieselguys unit does this so you have all the I beam can give you.
Phil P
PS: dieselguy if you get to Florida I really need a good welder it has been 50 years sense I did any stick welding and tried a little a few days ago and would need to spend a week practicing to get back where I was 50 years ago. LOL