Oh, then game play will not be a problem to you.
About the STA gears, you need to learn how to use Macro program for that. On some private servers, it is illegal but here, you can use it anytime you like. In case you don't know, Macro program is a 3rd party program that if used here at Mazey Flyff, can allow you to switch like 2+ gears in an instant. So basically, you need to learn how to use Macro and if you knew how, then buy STA gears.
Considering you have both ASAL Gears and STA Gears, here's what you will do. I'm not an expert with Macro, to be honest I never tried and used it, but this is just what I understand and heard about Macro switcher. Anyone is open to correct me. At siege, cast Asal using your ASAL Gears, and after you hit or killed an enemy, use Macro program to switch your gears to STA so that you can survive some hits while waiting for the cool down of ASAL. Once cool down is over, switch gears again using Macro then cast ASAL and switch again. That's what I understand about Macro.
In case you don't want the hassle of using Macro, you can always try using hybrid type FMs. Hybrid is basically a FM composed of different stat build(if i'm not mistaken). Meaning, you need the STR and INT awakes for ASAL plus you will add STA awakes so that you can have considerable amount of HP with considerable ASAL damage. This, I already tested. I got like around 280m hp or 300m hp if Im not mistaken and I had an ASAL of 700m. But it is still useless since FD YJ can just 1 hit me using HoP. So I quit the hybrid type.