Well, I'm learning about crops myself, this may help: https://forum.feed-the-beast.c…guide-very-indepth.14316/
Read the commentaries too, they correct somethings there. I believe +124 is enough for air quality, clear skies, and no block around the plants.
I just can't make myself to like forestry machines, so I will try using the IC² harvester. I used before, and liked, may need to spam a few, but they cover a 9x9 area, I don't think I will use a lot.
For maps, I use Rei minimap, as I can set a waypoint, which emit a beacon of light, so is very easy to use. it sets a point too, that you can see even trough walls.
Gregtech does have White Dyes, but seems that there's not recipe for them: http://ftb.gamepedia.com/Dye_(GregTech_5)
Another source are tulips, but I don't know if you can farm them.