I don't use CLark, but Terry I can give a few pointers.
Terry's Bread and Butter combos are cB, cA, df + D, hcf + D, f, f + D, f, f + D or sC, f + C, hcf + D, f, f + D, f, f + D.
Super Cancel combos off his 2nd hit of power charge (hcf + D, f, f + D) should "ALWAYS" be Super Canceled into Power Geyser. The reason I say this is because 2k3 has Damage Scaling on super cancels. So if you were to do cB, cA, df + D, hcf + D, f, f + D, (SC), qcf, qcf + B. Your gonna do less damage by SCing into Buster Wolf.
His best anti-air is df + C or A version Power Geyser. Best short jump attack is jD. Always throw out a weak power wave (qcf + A) after knockdown on a burning knuckle or power charge. When you throw out power wave, dash 2 steps and short jump with jumping D.
His far standing B and crouching D. Standing B is a great poke and can catch people off guard at times. If your quick, you can cancel into LDM Power Stream his other DM's. Now his cD is good for playing footsie. You can also cancel into special / super moves, upon a blocked / connected cD.
Good poke string when the opponent is blocking is cB, cA, df + D, hcf + D, f, f + D, cB, cA or just cB, cA, far sB, short jumping B/C, sC, f + C, into power charge x2. One more you can use is cB, cA, cD, burning Knuckle.
Oh yeah, NEVER use power dunk unless it's for combo / juggle purposes. Same goes for Kick Back..... I mean Crack Shoot. They both have horrid recovery time.
That''s all I can can come up with right now. Maybe I'll play some 2k3 later to see if I can remember anymore Terry stuff.