Welcome to ECF. I always use SS because it is safe in either wattage or TC. As you are discovering, your TC settings will, in part be based on how you vape. I like getting a coil set up for TC, but vaping it in wattage mode a while to see how it performs.
Typically, I use whatever wattage I enjoy in wattage mode as my "ramp up" to TC, and once the coil gets hot (you can't start at 0 wattage as the mod has nothing to "read" if the coil isn't first heated up. From there, you can see what temperature "ceiling" works for you. I keep my temps as puny as my wattage, but I am a MTL vaper. I use around 350 F, and it's rare (unless out and about with fewer vapes) for me to hit that ceiling, in fact I often will use wattage mode at home because I rotate my setups enough to find that I don't need my coil temp "'monitored" and I figure I'm just wasting battery life.
Of course, smok doesn't do a great TC. Please don't use it to "define" your TC experience-- because you won't enjoy it (potentially) and yes, there are other non DNA mods that do TC far better than smok, Teslacigs is one such manufacturer. I don't know what they did to their board, but my teslacigs mods are about as close to DNA mods as you can get, without actually purchasing a DNA mod. I learned to do TC on them and I was not disappointed.
Best of luck,
Anna