Leigh, watering pots can be quite challenging in that different pots need different cycling and amounts of water when they are watered. Depending on the amoount of pots, their sizing and watering needs many can be properly done with a dedicated clock of multiple programs and Mini-Valves to address each zone. Minivalves are still available and offer up to 9 or 10 gph. Drip heads can be selected by their hourly output and matching the pot to the program will probably solve your problem.
Your biggest/hardest choice is warranting the cost of such a system for just a few pots...
The Irrigation Specialist Mfg' Az.
Please check my website and you'll find what I do and the unique tools I make and market.
Real timesavers, especially the Suck-Tube and Krik-It.
http://www.tismaz.com