Wish it was that simple.
You need a magnifier to look at the tricomes, the beeds of resin will need to change color. also at in the same time sequence you will note the % of red hair. Note the type of hi is usualy by the color and changing of the tricomes.
Also the strain come in to play , some love x number days of TOTAL DARK, some are some are not.
Radio shack has the mag , usualy use the 30 power to look deep into the resin gland.
WAiiiiiiiiiiiting is a pain in the bud, relax and peek at the firm buds.