1) SBG has no basestrays for movement. Each model is moved on its own. WoTR is the one with bases/trays for movements
2) check out the Gallery or W.I.P. section. You'll find some truly amazing schemes, then all you have to do is PM the painter and ask if they could tell you how they did it; or use theirs as a guide. There is one that I can recall that actually has a beautiful scheme, it looks like honey pants, colorful cloaks, and converted hero's to look like those demons from 300.
3)jewels/metals/armour can all be painted in different ways. Again, dig a little and see what you find. There are a gazillion "How To.." on youtube, there are Miniature Painting sites with tutorials, and the old Journeybooks have very basic tutorials in them. You could even go to a hobby store and browse magazines from the rack and get ideas.
4) the reason I mention those are because its ...your... hobby. ...your... WarHost. In other words what I like may not be what you like. So it would be best if you find, on your own, a technique you like and if you can't figure how to paint it or get a response from the painter then link the picture and we can see about breaking the paints down for you.
so if i buy :
2 boxes of Haradrim warriors,
One box of plastic riders,
The betrayer(on horse as a hero for my riders)
one haradrim commanders box( heroes for my soldiers)
Since you are playing with the old rules we would need to know how many points you plan on playing with, but...yes this has the potential to be a good force. 12-24 Harad foot soldiers (depends on the boxes you get. The old box sold 24, the new ones sell 12 for the old price) and 6 cav. Is a decent force. Remember to have 33% bows, use the banner and take 2 captains (use the Taskmaster as a capt.) that should give you a solid reservoir of Might for the warriors. It would be best to do some mock-up of force list within the points you plan on fielding and then post that/those lists in the Army Help section of the forums. There you'll get a pool of more experienced players to critique and fine tune your list.