I have always reloaded at a normal desk, an older one that is very sturdy, and that has a plastic laminate top. I find a comfortable chair to be very important. Rather than modify the desk, I have made a mount for my press that clamps to the desk, and that raises the press up to a higher position, and turns it toward me. When I am using the press, I sit at an angle to the desk, with my knees on either side of an inside corner of one of the drawer pedestals. Between loading sessions, I store the press mount at the back of the desk's knee well. This setup gives me a lot of flexibility, allowing the desk to be useful for a variety of tasks while being well suited for loading. One thing that I have recently added to my equipment that relates to reloading bench design, is a way to look at my balance scale as if it was at eye level while it is on the desk top. I find this very convenient. It uses a prism and adjustable mount. This is the setup that I use when trickling powder charges.
If you decide to build your reloading bench rather than adapt a desk, let me make a couple of suggestions. Plywood panels that are screwed and glued to the ends and back will act as shear panels that will make the bench much more sturdy, and less susceptible to developing a wiggle as the wood shrinks causing the joints to loosen up. In any case, glue is a good addition to any cabinet construction project. I would also suggest that a top finish surface that is trapped in position by the tops edge trim is a good idea. That way you can put the bench to heavy use, when needed, secure in the knowledge that you can make the top finish as new, quickly and easily, by either flipping the original piece, or dropping in a new one. There are several candidates for this application, quarter inch plywood, tempered, or plain masonite, melmene, or any other kind of tough, smooth sheet material.
I would go easy on bolting things to the bench. A friend has a Dillon press, that he may use a couple of times a year, bolted to his garage work bench. It is in the way for many tasks that he does on a regular basis. If it were mine, I would install T nuts in the bench, and keep the press on a wall mount, with a dust cover on it, for those 363 days that it was not in use.
