I have a lot of customers that also use a block of wood to install their wheel seals, some successful and some not so. The design of the classic version of the scotseal is such that it will allow the top portion of the seal to bell or compress if struck after the seal has seated against the bearing race. This bending of the seal housing then causes either the sealing surface not to contact the inner wall of the seal or worst case result locks the movable inner seal member to the outer housing causing a groove to wear on the axle spindle that might require a speedi-sleeve or the axle surgeon to repair. When the installation tool is used you will hear a different metallic ring as the seal seats against the bearing race when you use the seal driver.
I scanned four pages of a CR installation for reference, but its too big to upload even page by page, if anyone's interested in this PM me and I'll send it to you.