ULTIMATE WEAPON SUCCESS RATE

Upgrading an Ultimate Weapon is trickier than a normal weapon. First you need a Shining Oricalkum, which is essentially 5 sunstones and 5 moonstones. On top of this, your uprgading chances are FAR lower than any other equipment you've attempted to upgrade so far. Your chances for each are as follows
MAKING UNIQUE WEAPON+10 TO ULTIMATE WEAPON = 2%

ULTIMATE WEAPON
+1 = 11%
+2 = 9%
+3 = 7%
+4 = 5%
+5 = 3%
+6 = 0.9%
+7 = 0.7%
+8 = 0.5%
+9 = 0.3%
+10 = 0.1%

Be prepared to be poor very quickly, and very often.

- Creating Gems

This is one of the more straight-forward parts of the whole process. Get a weapon above level 60, give it to the refine NPC and hope for the best. Depending on how far the weapon is upgraded will determine your chances of success and the possibility of gaining more Gems from a single weapon. Here's your success rates and amount of gems for each if successful:

+0 = 5% / 1 Gem
+1 = 10% / 1 Gem
+2 = 15% / 1 Gem
+3 = 20% / 1 Gem
+4 = 50% / 1 Gem
+5 = 100% / 1 Gem
+6 = 100% / 2 Gems
+7 = 100% / 3 Gems
+8 = 100% / 5 Gems
+9 = 100% / 10 Gems
+10 = 100% / 20 Gems