To the OP, a few design improvements that would help you significantly.
1) I really like the pass-under slider idea. It opens itself up to also being a skid plate mount. My concern is lateral movement once it hits a side impact on a rock. Those u-bolts are going to go snappy-snap on a good hit. Welding a locating block where you have that little bump that rests on the bottom side of the frame rail will give the sliders a ton of additional strength against lateral impacts. I’m not sure how strong they are against vertical impacts if it’s just u-bolts, but if there are enough of them I’m sure they’re strong.
2) You need to re-orient those bolts for the skid plates. You’re going to sheer them off the way they’re currently sitting. Turning them upside down so that the head is down on the bolt will help. If you don’t have a way to manufacture a recessed bolt head underneath, then boring out the hole to a square hole and using a carriage bolt that faces upwards would also be a drastic improvement. But having those bolts facing downwards is just asking them to grab a rock and get ripped off.