New to 400m

I’m not an expert, and there are several on this board that may chime in, but I’ll start it off. If he is capable of 23.2 for 200m, then 24.3 (+1.1) is about right for the first 200m. His second 200m split is then 28.37, and that is the real area that needs addressing. My personal opinion would be to keep the first 200m fairly close to +1, or maybe +1.5, and work on special endurance to bring up the second 200m split. How to do that during the season is a little beyond my expertise, and hopefully others will offer suggestions.