Realize that the new valve guide materials (silicon bronze) materials is superior to original materials like the copper and brass guides used previously. I have used Canyon Valve guides, which are silicone bronze, also with good results. Sizing (OD)is the difficult decision to make. Too small a diameter and they may come loose. Too tight and the guide may be damaged during installing . Intermediate repair sizes are offered by some manufactures, which is slightly oversize to make a good fit. They are not a full oversize.
My advice, use a good experienced machine shop. Supply them with all the Technical specifications and installation process. So they can make an experienced judgment call on sizes to use after measuring and inspecting the head. I even loan the machine shop my special factory valve guide installation tools to use for the work.