ghost ore is probably pretty cheap now and you can get to 600 just by making the items that show as green skill points. You will mostly likely make a few and will also most likly make a couple blues along the way that you can sell to help offset the cost of buying ore.
I'd use spirits of harmony to make something usefull instead of using it to make something just for a skillup.
Its much more possible (on my server) for Tailoring and LW due to the cost of materials. Cloth is 10g a stack, so I just powered it to 600 selling off the blues and DE the greens. Ditto with exotic leather for LW... BS on the other hand is fighting JC for ore availability. That is keeping the price high as players are churning through ore for JC to get blues/daily research materials.
Remember you only need 595 with DMF coming up. As a Tailor/Enchanter on my main (Tailor can be done without spirits aswell, costs a lot of cloth, but then again, cloth costs litteraly nothing, Enchanting was even easier with all the crafted items I could DE, a no brainer), LW, Alchemy, JC, Mining were very cheap and easy to skill up to 600 as a 85 without spirits. LW was so cheap, I made more money from selling the DE mats then the Leather costed me. I leveled my Engineer tot 595, did that with a full mining back of ore (36 stacks, had some bars left though). Currenlty busy with my BS, I want it to 595, but it is a bit expensive all, when all yellow turns to green, I will create the cheapest green item, and hit Zen master trough DMF.
Havent done Skinning, because there is no real need atm, Herbalism is rather useless as 85, as you want to herb in area's above lvl 85, and I simply dont have a Inscriptionist.