Depends on the hybrid and what I want from that particular plant.
If it's a Sativa dominant strain and I want to maximize the sativa effects (head high/euphoria/trippy/etc) then I harvest like I would a sativa (while the trichs are milky/before they turn amber), if I want to highlight the Indica heritage (couch lock/mellow/pain relief/etc) then I'd wait till the trichs turn amber.
If it's an Indica dominant strain and I want to go all in on the Indica heritage then I'd wait to the trichs turn amber, but if I wanted to highlight the Sativa side I'd harvest before the trichs turn amber.
Picking harvest times isn't going to make a Sativa strain an Indica one but it can tweak the effects quite a bit. Harvest based on your own preferences. :)
I always just check the trichs. Get a pocket microscope and base it on how the trichromes look. I harvest sativa strains while the trichs are still milky and haven't turned amber yet. I let my indicas go all the way and when I can spot check a plant and most the trichs I see are amber I know it's good to chop.
I've never got seeds from anywhere but Nirvana. Ok, that's probably a lie. But, I've never bought seeds from anywhere but Nirvana after discovering Nirvana and I've been buying seeds from them for years now. I feel you on the strains though, I've also been "lobbying" for Nirvana to get a psychedelic strain for years... I've already got this years grow going but I might have to branch out to explore a bit next year. I wish I wouldn't have to though, Nirvana has always been top notch both in seed quality and customer service.
It's that time of year again, you know what I'm talking about, time to get those gardens started! If you're an outdoor grower at least, indoor growers can do whatever the hell they want I guess. Heh. Anyway, last year I had 10 plants of Blue Dream growing in my greenhouse. They came out ok but the heat stressed the plants out near the end, greenhouse was probably hitting 95-100+ on hot days... Not good. This year I've added two extra vents two the greenhouse, both near the top of the front/back sides (the vents that were built into the greenhouse are near the bottom. Why?. Hot air rises...), and put a high velocity fan in to help with air flow. It'll still get hot in there but with the increased ventilation and air flow I think it'll be fine. Blue Dream was nice, but this year I decided to grow some Durban Poison and Hindu Kush. All but 1 seed sprouted but that's ok, 9/10 ain't bad! Well I don't want to be too wordy, but lets all enjoy growing some weed this year!