I've always used http://www.swtor-spy.com/companions/
for affection stuff for companions, also a good site to look at how weapons, armor, and anything else looks with their 3D views. Good way to find stuff.
As far as the blues and purples bit instead of levels maybe I should have said moderate, abundant, rich. Looks like it's all crit based anyways from what I've found so that one was answered in that spot too.
As far as selling things I usually go with green = lvl x 100, blue = lvl x 200, and purples are lvl X 1000, all over those are over GTN prices and will usually sell within a week or so of relisting. Low lvl purples go like crazy, although you have to be careful since sometimes you can sell the individual mats for more than what you sell the final product. I usually have my "Crafting" companion at "I have 10,000 love for Corso and Corso has 10,000 love for me". So any crit doubles I sell.
Diplomacy is awesome (I have a Biotech 50 and plus the companion gifts are nice) since you also can use that for offsetting some of those nasty opposite alignment hits you take during cut scenes. Will you kill this guy or turn him over for unending torture!?!?! Umm....I kill the guy, i wouldn't want to live through that. DARK SIDE POINTS! WTF? SO leaving this guy to be tortured without end is a good idea?
Another point I would say is if you don't care about the spoiler of who your companions are going to be I would check to see what all their skills are. Nothing sucks worse than grining your way through Artificing with a Marauder only to find out you don't have any companions that give you boosts for it. Although a complete flip to a new profession doesn't take to long when you're 50 and sending out 5 guys at a time. See who they are and how they can fit into your professions, that double production on crits sure is nice when you're making purples.
I've got some more Q's for ya and I'll send them your way, however won't feel upset if ya don't use them since I already cornered the market on this Crafting Corner.
Thanks guys and another great cast!