If all he wants to do is ID the cam to see it it's too hot for his otherwise stock engine then the 0.050 figure would be fine, I think.
I'm running a 220* at 0.050 and it's a bit to long for my current setup, which is 9:1 static compression. I want it to pull well at 2500 and it pulls at 2850. The advertised duration is 252* In. and Exh. A 264* cam is going to be a bit hotter all other things being equal. So it'll pull closer to 3,000 RPM. That duration should have at least 9:1, preferably higher and a stock 228 is nowhere near that. I'd hunt up the stock cam to go with the stock Zenith 228. With a fresh overhaul it'll be a sweet ride.