knapmich,
The original hat channels had wood inserts. That retained moisture, then it would rot leaving behind rusted out hat channels.
You will need some type of crush sleeve to support the bolts.
I too have the Classic Enterprise hat channels and have the same round crush sleeves. This method (hopefully) will reduce moisture retention and help it last longer.
There is one body mount directly under the tank that is different. Originally there was a captured nut. Classic Enterprises didn't account for that (maybe it's been updated). I had to get a captured nut for the body shop to replace that crush sleeve. This avoids a bolt head underneath the tank and any hat channel crushing.