Per Federal DOT regs. you can use one chain to attach the front at 2 corners and one at the rear fastened at two corners to secure the load. The chain must be rated at full load capacity so you need to know exactly what the rig weighs. Chains must be stamped with the material grade or they get automatically rated as grade 30 proof which is the lowest grade made. Any nylon straps used must be printed with the rating on it also. The DOT regs dont require that FEL or Backhoe be separately strapped as they quote that you must fix it like an automobile.
I recently hauled both my B 26 TLB (500 miles) and Yanmar 4220with FEL with Bush hog (200 miles) chained front and rear. THe B26 has tie down hooks front and rear on the tractor frame so that is what I ran the chains thru and then used a binder on one side to tighten them. Since I had 2 each 10K nylon straps I went ahead and strapped down the FEL which was firmly setting on the traile by passing one strap over the FEL arms and ratcheting it tight. The other I passed around the backhoe which was raised and locked into position and the swing pin locked in. I really dont think I would have needed tolegally tie in these two "attachments" since they are not really attachments but part of the TLB, but due to comments here on TBN about certain LEO's with varying opinions on interpretation of regulations, I went with the strapping.
I also strapped the tail wheel of the bush hog on the 4220 for safety as that really is an attachment. I went over some pretty good bumps in the road as normal in Louisiana highways with no issues. I stopped a couple of times to check the chains for tightness and snugged up any slack.