Whatever you do, it's important to clean and dry the surface well.

Aquaseal is great. The company that makes it, McNett, told me that Seam Grip (a similar product to Aquaseal -- both made by McNett) works well for sealing small holes in Thermarest pads -- just a drop of Seam Grip alone, no patch necessary.

Someone who works at REI told me that after playing around with all the different sealants and adhesives, he found Seam Grip to be exceptionally and uniquely strong and lasting.

(McNett also makes a product that is designed for coating or recoating and resealing a leaking tent fly.)

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To your original question about a tube patch: The products made for patching tubes are different. They are made to work with different materials. They might do the job, but the McNett products would be stronger and less likely to let you down.

IMHO, it's better to do it right so you don't have to redo it later, and so your sleep isn't a disappointment when an unreliable patch lets you down.