GRX RD capacity

We all know Shimano has been conservative on their capacity, but does anyone have any experience with the new grx?
I’m looking to run a double with 46/36 up front and a 11-34 out back. That would require 33t capacity, but the 812 rd is listed at 31t. The longer cage 810 rd is listed at 40t capacity.
I’d love to stick with the shorter cage and I think it would work, just looking for some real world experience if anyone has any.
If not, I may be the guinea pig.

The RD-RX812 has a 31T max capacity, but it also seems to require a lowest cog of at least 40T and no more than 44T. So total capacity may not be the only compatibility question.

I’m currently running the RD-RX810 with a 46/36 chainring and 11-34 cassette, and it works flawlessly. I have not yet found myself wishing I had the 812.

Still, if you give it a try, please report the results.

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Thanks for that! I was so caught up in capacity I didn’t think about the min low cog. I guess that answers that. I’ll run the 810 and not worry about it.

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I know you’re asking about a double up front but in case it’s of any use to anyone else I use an RD812 with an 11-46 cassette and a 42t chainring. It works perfectly.