Looks like you are learning your smoker, that’s good, those WSM are great smokers, I saw a thread here with smoked tuna too, I’m gonna have to try some fish.
Sounds like you are doing what I’ve done, using just charcoal without any smoke taste so that I could learn what the different woods taste like.
This might help you with lowering your start up time, waiting 30 minutes before it’s at temperature and cut down on the white smoke at the beginning.
I cut both ends out of a #10 can, then took a can opener and cut holes all around one end.
I fill my charcoal ring with lump and place a fire starting brick directly on the charcoal and light it, place the #10 can over the lit brick and then add lump on top of it, a little or a lot depending on what temp I’ll be cooking at.
When the lump in the #10 can is burning good I pull it off and assembly my WSM, I made a bracket to hold the door open about an inch and a half when it is positioned upside down, it kind of acts like a turbo charger.
I’m usually at 225° in 10-20 minutes depending on how much lump I put in the #10 can.
I hope that helps.