Attachments Suspension for Sears 1976 ST10

Haven't posted on here in a while, but need some input on shocks and leaf springs for a vintage Sears ST10 lawn tractor. I'm going to build a custom make over of this little mower. Here's what is planned: 18" leaf springs for the rear trans axle, (removing the bolts that hold the tranny to the frame and plasma cutting 2-3" curvature on each side of the frame to allow axle movement. (2) fabricating shock mounts to the frame and axle supports. (3) cutting an extra 1/2" into the front frame lip to allow 2" up-down movement of the pivoting front axle. (4) fabricating shock mounts to the frame and the pivoting front axle. My question concerns the shocks I found that are short enough and with 2" piston travel. The shocks I chose are used on a Arctic Cat snowmobile, part# 04-250. Anyone have an idea if these shocks would be soft enough to dampen the ride over rough ground, or would they be too stiff for the weight( guessing around 350-400lb for the tractor. If the springs are too stiff for the mower, I can experiment by removing springs from the 3 leaf unit. I forgot to mention I've already replaced the 10HP Tecumseh with a new GX620 v-twin Honda engine. The gas tank and rear fenders will be from a Sears SS16 that had the tank in the rear and fenders indented for the larger plastic tank. Plan to also use the flip seat brackets from the SS16 along with a new shock-spring loaded seat. Just need some input if the shocks I've chosen would be suited for the weight of the machine. Thanks for any input.