I don't have the measurement for your 5er, but having installed a set, I saw the only difference between the two kits is that the one for over 58" has an extra mounting plate for the front side to side arms, so they can be separated in the middle
If you look at the left side of the picture below, instead of a double mount like miner have you get an extra plate, backing plate and a couple bolts so the center mount can be separated.
ON EDIT: We just setup again yesterday, and all I can say is ****, Rock Solid and I don't use X Chocks!
Do as the instructions state, with trailer just a tick low in the front. Rear jacks 1st, put some upward tension on, and lock arms. Then lock front arms and rise about 1/4" to 1/2", this puts all the arms under tension or compression, no wiggle!!
Well some things seem to change, now the instructions speak of greater than 66" or less than 66" between the legs. I checked before I started my install and all tubes were the same length.
Install instructions
Russ & Paula the Beagle Belle.
2016 Ram Laramie 3500 Aisin DRW 4X4 Long bed.
2005 Copper Canyon 293 FWSLS, 32' GVWR 12,360#
"Visit and Enjoy Oregon State Parks"