Yep, thinking about frogs in here . Terrestrial tarantula adults can break open their abdomens with a large fall (couple feet as in from someones hands) and it's usually fatal. Not sure what is the limit in height or if there is a factual size/height relationship .

I start offering water in bottle caps at around 2 in. legs span. Can spray more, but again, humidity is not critical like in frogs. Could try covering some of top screening to increase humidity like we do with frogs.