I would start with 3 cams and max out at 6 but most likely end up with only 5 cameras.
Cams would be 8MP no plans for any PTZ.
Would this be a good build?
POE -LINKSYS LGS308P 8-Port Business Smart Gigabit PoE+ Switch - Newegg.com
PC - support for H.265
1. HP ProDesk 600 G2 SFF Intel i5-6500...