Does pot size matter

No its just stability, the roots will exit the pot and fill the table. You don't even need pots on a ebb&flow table. Keep an eye on the drain and roots. Don't want any uncontrolled floods from a clog. Good luck and Happy growing

Oh what a great question! I'm conducting an experiment as we speak with two of my Blackberry Moonrocks... 1 is in a 3 gallon pot, the other in a 5 gallon pot - both germinated within 3 days of each other, both treated exactly the same - the one in the 3 gallon is literally 5 or 6" taller and has far more bud sites on her than the one in the 5-gallon. I germinated two others about 2 weeks later than these two ladies (in 3 gallon pots) and the lady in the 5 gallon is the shortest of them ALL.... I'm actually wondering if the silly plant is spending more time developing roots in the larger pot than growth above the soil! Now, they are all only about 4-6 weeks old so I can't tell you what is going to happen to them between now and harvest but for MY money, I'm going to stick with the 3-gallon pots for all my grows... saves on soil, saves on nutes, sort of saves on space.... Good luck!