It's not gonna matter, you're gonna farm all the other gear pieces that will become bis anyways. Just level a toon to 44 now and gear it to have some potentially scaled stuff, or level your twink once SL hits. You're gonna replace every single piece you have now anyways. Literally doesn't matter.
If you have sentimental value to your twink, then do the whole lvl 44 or a fresh 19 SL twink and let your old 19 sit at lvl 9 for flex.
It's really not as bad as everyone puts it out to be if you just take a moment and actually think about it.
With the current exp buff, lvling to 44 takes fuck all amount of effort. It's so fast.