Lookin' mighty tasty!!! I noticed you identified each type with a tag on the pan so you can differentiate between them for preferences to reference to later on with the next smoke...good planning makes for successively better dining. Nice work!!!
As for the sticky sugar issue, your ratio of sugar to herbs/spices/salt may be a bit excessive, but also note that sugars tend to caramelize quite a bit at higher temps or with longer smokes on open grates, so you may have a couple things going against you with that. Try to run a bit lower temps and add 3/4 hour if needed to complete the cooking to your desired amount (by pull-back, bend-test, whatever works for you). If that doesn't give better results with the sugar, then I'd suggest on cutting back the amount of sugar at least 1/3, possibly 1/2, and roll with that for the third round (or whichever change you want to try first).
On second look, I don't see much in the way of a darker carmelization, except on the no-foil ribs. Are those the ones with the stickiness, or was it with all of them? If it is with all of them, I'd say too much sugar, if not, then I'd reduce smoke chamber temps a bit.
Damn fine first rib smoke with the new WSM, Wormser!!!
BTW, if you give up on sugar in the rubs like I did years ago, try dried red bell peppers in your spice grinder and replace the sugar with that, only use quite a bit less, of course...mildly spicy with a sweet background...we love dry rubs based on RBP...it won't scorch on a long smoke, no sugar stickiness, and still gives a great bark on the meat if you want it. Give me a shout if you're interested.