Either will work but IMO id go with injection then maybe pick a few open pours to play with. With injection you get perfect baits every time. For me, i also like a bait that is fully rounded without the flat spot.
That being said, if you ever want to play around with a design you came up with, you can make open pour molds fairly easy an they're fun to play around with. Either kind will catch you fish, but there are a lot fewer open pour molds
-Jeremiah