Converting your total weight of 1,350lb, converting it to Kg = 613Kg. Divide that by 4 mounts and round up a little and you get 160Kg per mount.
Just going on static weight and using the column for thrust taking applications (*M-Max) the 17-1609-65 has a max capacity of 210 Kg.
The envelope for these mounts is pretty wide, so it would probably be "safe" to use this size for all 4 mounts. (There is a reserve capacity of 100Kg for the 2 aft mounts) If the after mounts are loaded a little more due to the gear weight they will just deflect a little less, but we're talking fractions of a mm. At this loading these mounts will deflect under a static load a little over 3mm.
The next capacity size up shore 75 has a max capacity of 315Kg and will deflect a full mm less at 160Kg loading.
Without center of gravity and exact mount locations in relation to C/G I doubt you're not going to get any closer. Hopefully there's a TF member with the same setup that will chime in.