Entry way systems

I read recently in a thread that someone was claiming Entry Vestibules are required. Nowhere in the reference guide am I reading this. We have a rear entrance for an infrequent, special use that will require a key to enter. We are planning on putting a roll out mat here. From what I read in the guide, this should meet the intent of credit, Correct? Finally, Can a combination of walk off/roll out mats and a grill system be used together to make up 10ft in the direction of travel? We have grill systems that are between 3' and 6' long. We have been planning on installing roll out mats to make up for the remaining to equal 10 feet. All will be cleaned/serviced on a weekly basis.