Couple of questions about DWC

What type of air stones should I use for DWC. Ive heard from someone who owned a hydro store that some are better than others, though the ones he was selling were very expensive. You need smaller bubbles for DWC, is my understanding.

Also I'm not sure what air pump(s) to use and whether to use 5 gallon or 2 gallon buckets. Thanks in advance for any info you can give me.

I use 2 inch cylinders and 1 inch at 2dollars each work like a champ. No need for expensive ones as they are in business on making profits not how well the profuct works.