The main stat of a Dual Blade is LUK and secondary stat is DEX and STR.
Please do not add STR or INT!
As of Tempest patch you don't need to add in any secondary stat.
Purely Dexless: Have a Base DEX of 4
most recommended REGARDLESS of funds
Honestly, this is the only build I would recommend for AP.
Tempest patch doesn't require any secondary stats at all to equip.