Both seatposts you mention use an air spring, with a hydraulic release. There is no maximum weight listed for either one.
They are designed to use your body weight to drop the saddle when the remote lever is pressed, and to use an air spring to return it to full height the next time it is pressed. You need to be off the seat when the lever is pressed to return the seat to its normal position, regardless of your body weight.
In addition, I'm a big dude, and I have no issues with mine that are weight based. I wouldn't be worried about it.
The Rock Shox Reverb is a solid unit, and the crank brothers design looks to be as well, although I've only ridden the Reverb. The one issue I've seen is that the remote levers are exposed, and sensitive to impact. I've damaged mine by resting the bike on the handlebar to cha nge a flat, even done carefully.
Bright side is, parts are cheap and easy to find, and the bleed process is easy.
I do recommend the Reverb.