My temps are typically 80 year round and I keep my dehumidifier set to 50% RH during the winter. It is typically 40-50% RH during the summer without the dehumidifier due to more outside venting. 50% RH isn't going to make bigger calyx or denser danker flowers, it's just that, keeping your RH at 50% and not higher should help prevent botrytis. Lots of people are confused about PM though, high RH doesn't cause PM, PM thrives in lower RH at 70 degrees, according to a study I recall. If you use LEDs, your grow will be much happier and healthier at 80 degrees or even a little warmer, over 70-74.