The ilvl of the crafted amu need to 90 or higher
The formula is ilvl=input lvl/2+clvl/2 (dropping fractions)
That means that if you use the same character to gamble (ilvl = clvl -5/+4) and craft amulets you'll want to be level 93 or higher.
Worst case scenario. You gamble an amu with an ilvl of **
ilvl = **/2+93/2
ilvl = 44 + 46
ilvl = 90 = +2 skills possible on every amu you gamble-craft.