Do not add more ZDDP. 1150ppm is plenty. Too much and the phosphorus portion of the ZDDP will react with combustion by products and make the oil acidic. It's a balance. Too little is bad, too much is also bad. You don't need more than ~1400ppm, and adding a ZDDP additive to a fill of something that's already at 1150 is going to launch you over 2000ppm. That's too high.
It's a good oil for a cam break-in. What it isn't good at is extended time at high temperatures. It'll break down above 240-ish degrees and start sludging not far above that. It's fine for a daily. But if you're beating on it at all I'd look for a synthetic with more temperature tolerance or go with a really short change interval on the Rotella, like 2000 miles or less. The only way to be sure would be to run it and have it analyzed at a lab to see what shape the oil was in and adjust the change interval according to those results.