how many high-res textures for archviz?

hello, i want to make very high quality archviz cinematic. light is baked and i have gtx970 and i really dont care frame rate as long as i can edit the scene. my question is how many 8K textures i can use for materials whats the best format to export for that purpose from substance painter? my textures looks too lowres to me when i get too close to walls etc.