Assuming 2.35" tires the gear inches will increase by 9.3% with the 29er vs 26er and the same cogset / ring. So a 30T ring on the 26er would translate into about a 27T ring on a 29er. I would lean towards something a lot smaller than 32T to be honest, unless you are not climbing. I would maybe go with a 24T since that would give you 30km/h @ 100rpm in the 11T in case you need to ride a considerable distance on the road. I don’t think you would need a bigger gear than that unless you are racing and you are very fast.
At AHC '15 I was climbing in the 22 x 34 on my 26er and that wasn’t easy. I passed a lot of people despite riding in my lowest gear. They were walking.
EDIT: Having said that, I didn’t consider BCD in my calculation. Perhaps the smallest you can use is like a 30T? I don’t know.