The ideal environment for drying is to try to maintain 60F and 60% humidity with a fan blowing air GENTLY around the buds, not directly at them. But that still is not going to guarantee a long drying period... airy buds, for example, will dry much faster than buds that are hard, dense rocks... When you jar them up, you can put in some Boveda 62 which will ensure the moisture content of the jar... you could try Grove Bags (they're great but too expensive for me)... I've never had a clue what humidity is inside my jars (although I DO use the Boveda when I can)... if my buds are too dry, I will put them in a ziplock bag with a slice of bread (like you would soften rock hard brown sugar)... some people use a leaf or two of lettuce... if they're too wet, I put them on a plate somewhere and let them dry out a bit more.
You're worried about the length of your drying - there's no "magic" number of days, believe me! I judge when the buds are ready to be jarred by gently squeezing them - they should be slightly spongy but not overly so... in time, you'll get to know the right feel.... that might take 4 days, it might take 7, it might take 10.... The drying time for my first grow was only 3 days... but the product was stupendous.... my most recent harvest dried in 6 days... the drying time does not affect the taste, only the smokeability... dry buds will be harsher and used up more quickly, wetter buds won't light as well nor keep going without re-lighting...
Good luck... I'd just suggest you not try to achieve absolute perfection - roll a joint and relax! :-D