RHI too high ?

That depends on temperature and where you are in the life cycle of the plant -- See VPD chart i have linked in my profile comment section. check out the other links too - great info to create a proper perspective on how things work in the natural world. lower humidity around 40% is great for trichome production. Keep that up if you can... if you can't, don't worry about things you don't control, or if you do, start controlling them :) Get a dehum/ac/heater combo, lol.. "get'er done" if it is essential for you. Yes, it will be more optimal, but your lights are the limiting factor 99% of the time. if they say you get a "25%" increase doing this (totally made up bogus % to show concept), that's under optimal environmental conditions and microdosing feed and 1500-2000umol/s per m^2 energy, lol... otherwise, it'll be far, far less than whatever supposed %-increase listed. If you do all that stuff, it's accurate information to go by.