I've had all sorts of "waterproof" gloves, and the above is the only real waterproof solution. The only drawback is that your sweat will not escape and will dampen your gloves from the inside.
The Aerostich will eventually leak at the seams in a sustained downpour, we've got two sets with the same problem. I have to continually treat them with Nikwax to keep them waterproof.
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For what it's worth, my Aerostich Triple Digits never have leaked. I have had them for about 140,000 km, with likely a many thousands of km's of riding with them in rain. I did toss them in the washing machine when I waterproofed my Roadcrafter last year; but that was more of a "why not" thing and likely wouldn't help if the seams were leaking in any event.
..Tom