I always did (with 1 Stock): s.HP - 236MK - l.MK - 214MK (should be around 25% damage) and you get oki. You can also end this with level 1 or level 3. I would not recommend 623 OD, it's too expensive for the damage you get.

Since the big update, it's also possible to do s.HP - 236MK - s.LK - 623LP without any stocks and meter, and it also gives good oki.