I'd say just smelt whatever weapon you prefer, at level 55 I do have a choice for more powerful bows, but I'm sticking with the 4 failnaughts I've had since level 41 just because each gives me +5 dex (and the fact I've dumped more money into them than I can remember)... As you get higher level weapons, no matter they type, they're all going to get expensive to smelt.
And save your smelting items, especially the reset button for smelting past +70. At first I thought when the smelting failed, you just loose the weapon you choose as the material, but the first time I smelted my +70 failnaught, the failure ended with both weapons being destroyed. I lost millions.. plus it had two ougi skills T_T... That being said, I wouldn't recommend you attach any ougi skills either until you're just about done smelting you weapon.