If he is a hoser (and he probably will be if he already sprays or can smell another cat), it is NOT a pleasant smell at all. The BEST room to keep him in will be a bathroom, laundry room, or somewhere with minimal surface to clean. You will need a blacklight to find and completely clean all spots....black lights do not show too well on dark surfaces. If you have floor boards or mouldings around the floor, the urine will get behind it unless you have a really good waterproof caulking job done first. To clean, use an enzymatic cleaner...follow the directions (if it says 5 minutes, leave it 10). Then wipe off with a dry cloth. Then wipe again with a 5% bleach and very hot water solution.
You may also want to consider doggy diapers if you want him to come out of the small room. I am currently experimenting with making my own fabric ones and using adult incontinence/doggy piddle pads inside. (you can google feline stud pants). Right now, I am thankful Luna only spray when she is calling....and Simba very rarely when Luna is in heat.
...Always in my heart... Mocha....Nov. 13, 2002 - Dec. 6, 2013
.... Slave to Bengal Cats....Luna, Mystik, Simba, Komet, Meli,
Spark, and Star
.....and a collection of kittens at various times.