well it depends on what type of high you want. you can harvest early when the tichs are at 25% amber to get a more cerebral head high, or you can harvest late when ATLEAST 75% of the trichs have become amber giving you more of a body stone. and yes if you want to try and have both a cerebral and a body high, you need to catch the maturity at 50% amberness(which is absolute peak ripeness). this maturity window is usualy within 2 weeks so just keep an eye on em...BUT, if you wait till late on a sativa it will not take full advantage of the strain(since sativas are known for there well head highs), just as if you harvest early on a indica strain, it will not take full advantage of the strain(as they are best known for there body stone).

now that being said heres what i would do if you plan to keep this strain and want to find out what the best time to harvest is for the future reference. take a few samples off a the plant at say 6 weeks(trichs should starting to turn), 7 weeks(trichs should be almost half amber), and at 8 weeks(when trichs should be mostly amber). dry them, cure them, just as you would normally do, then smoke it to see what "effects" you get from each. this way you will be able to tell which one you like and what "helps" you the best. :thumbsup:

good luck and let us know what you decide to do!:jointsmile:
The G13Budsmoker:jointsmile: