Round up. I.e. starting with zero or one, add 1. Since peak was 4 and 2, you also could try increasing to up peak for both. Monitor results.
If you're not tight on free RAM, it's easier to be generous when increasing buffer values. I suspect initial default values probably more tied to when router RAM was more restricted, and/or large MTU (e.g. jumbo Ethernet) wasn't possible or as common.
We are pleased to announce availability of Beta software for 16.6.3. 16.6.3 will be the second rebuild on the 16.6 release train targeted towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are looking for early feedback from custome...