GTechniq C1 certainly looks promising! I'm assuming you'd recommend it over CQuartz for this purpose?
Both are excellent coatings.
But if you are planning doing a combo, yes, I would choose Gtechniq, although CQuartz can be layered as well.
C1 for hardness, and Exo for slickness.
According to an email I received from Gtechniq, when I asked more info regarding the combo application procedures, the interval between C1 and Exo should be 4 hours.
Just watch out for high spots, correct it before curing, or else you'll have to polish it again.
Keep in mind that the second application will darken the color a bit, therefore Exo application must be checked thoroughly, in good light conditions.
As all coatings, I do it first thing in the morning, when you are fresh and more alert, no more late night/last thing coating for me, I would come back in the morning and find mistakes and the coating was cured already, and regret it.
It is tricky, but if you patient and zealous, you can do it.
Best regards, any doubt pm me if you want it, and I hope it helps a bit.