I think the reason why AG say not to put a wax on top of UDS is because a wax may not bond to UDS, at least thats what i think they mean.
At the end of the day your wax is mainly your protection, it's what you do before you put the wax on that will give you your shine ie, polishing, claying ect.
Personaly i use Super Resin Polish then a good quality wax, i have used Super Resin Polish and then UDS on top of that on my previous black car and the result was fantastic but i didnt put a further wax on top again. I will say that i found UDS harder to buff off than Super Resin Rolish, i guess thats because it contains some wax properties.
What colour is your car ? as you probably know darker colours are less forgiving if you dont get your polishing/waxing right, i've seen me spending a full day on my previous black Astra thinking i had a perfect finish then i would drive into a garage forecourt at night and their lights would show up all the bits that had left smudges or a slight swirls, that couldnt be seen in normal light. Black is a beast of colour to look after, however it's awsome if done right.
I have to say that white is so easy, and it just seems to stay cleaner for longer.
Like you i get a bit confused by these detailing sprays, do they go on after polishing but before waxing or after polishing and waxing or in between washing, polishing, waxing and so on and so on !!!!!!
I know one thing, i dont like the idea of these "waterless spray shine" thingies, you just spray your dirty cay then wipe off for a showroom shine, what a load of b******s.