Shaak Ti takes Force:
Her telekinesis is better, capable of holding an ocean back and breaking Starkiller's defenses.
Her kinetite is also a serious strength here Katarn would have to avoid.
Her tutaminis was strong enough to contend with Starkiller's Force Lightning and Grievous' lightsaber blades.
Shaak Ti takes sabers:
Her mastery and hybridisation of Makashi and Ataru is exactly what Katarn's Djem So does not do well against. Her outskilling Starkiller and numerous MagnaGuards is also likely better than anything Kyle has done.
Shaak Ti takes physical:
Her speed is greater, almost completely overwhelming Starkiller's. She is stronger, capable of matching a dozen magnaguards in one blade lock, she also held off Starkiller's strength. Endurance and stamina goes her way pretty definitively as well.
Honestly I don't see anything Katarn has an advantage in.