I am also sensitive to metallic flavors therefore using a screen mesh wick and tight draw is not ideal for me.
It's interesting that you're sensitive to metallic flavors, as I am quite sensitive to many other forms of wicking, namely, cotton. I abandoned rba's years ago due to never being able to shake the nasty taste of whatever wicking I was using. If it were cotton, I'd always taste it, and the same with other types of wicking as well. I always found it interesting that I loved the flavor in an old school 510, even though I used the same wicking in a rebuildable, but could not replicate the taste! I eventually, without any concrete proof, attributed it to the SS mesh that surrounds the ceramic cup in a 510 atty, and just continued to drip.
However! I've recently delved back into trying cotton, specifically, that Japanese organic stuff, and it's seemingly much better than all of the crap I tried the past. Still can't get Boba's to wick worth a damn in a tank, but I can at least use it for higher PG juices, and still have it taste decent, even great.