The inlets on the cowl are plenty big enough. No issues there at all. The front baffle you have built is a very good start. There are two things that I would do to assure good cooling. One would be to construct and install an upper baffle, or top if you will, that extends over the engine from the forward baffle and angle it downward after clearing the head to get the air flowing the direction I wanted it to go, which is down and out. A big open area behind the baffle and in front of the firewall creates a lot of turbulence. In not being directed anywhere it's entering the front of the baffle and slamming into the firewall, creating a big "roil" in there and not going out as quickly as it should. The other thing I would do is assure that I had a large exit area for the hot air to exit. That area can be reduced some whith the addition of an air dam at the bottom of the cowl, forward of the opening but they can be a pain to do at times.

Dick Hanson posted a picture in this forum a couple of weeks back that well depicted an upper baffle and the way it would direct air. It would not have to be done as well as his but something along similar lines would make the good start you already have into an excellent finished product.