I think if you're going to use terra cotta pots for citronella candles (which usually have a bigger wick) you should probably use the ones that have a fired sealant on the inside. I make terra cotta pots for candles (small ones) and use the modge podge to seal them, but I'm also using smaller wicks with these and will NOT under any circumstances refill these after they've been burned once (except for myself). As for the tins, seamless would be best, but I also paint the seamed tins with modge podge, but then again, the ones I use are smaller, so again, smaller wicks. You CAN find seamless buckets for these candles, I've seen citronella candles in these, so some supplier has to have them-just a matter of hunting them down (which is such a PITA). Good luck, and if you find some, please share.