I settled on 4 Wolfpack’s with the flat top.
The Wolf Pack has a grooves running across the top that a strap grabs. They stay nice and tight on the rack when strapped down.
I found that. 1.5” strap will fit into the “hinge” area on each side, but barely stay in the “groove" across the width. If you want to strap it length wise it would not work as well. I guess if you crank the hell out of the strap.... but on rough roads I can only wonder if the box would crack or come loose.
I then had the need to buy 2 of the hi 4” lids, and upon arrival noticed the grooves are deeper and well defined for the straps! Much Better! Ordering 2 more.
Even if the bracket holes do not correspond to the rack spacing it can be done. I put Baja Rack items on my Front Runner rack by simply drilling holes in the base to properly space the item. A little paint and you're done.
Drilling is the only option. I called Front Runner and the guy pulled a spec sheet and told me the mount hole mounts on the rack are 22”. (Great Cust Svc). Upon measuring the Rhino Rack There is no possible combination to mount the rack without drilling.
I so wish I would have gone with the Front Runner rack. Better accessories, more of them, WAY better prices, and WAY better customer service. Have had to call them 3 times with my daft questions- to successful answers, while Rhino Rack has failed in this dept. more than once. I thought I did my research, haha.
Thanks for the input people, much appreciated!