Hey, congrats! That's a big step.
My thoughts...
• A sheet of coarser plywood under the existing top, OR place a 24x24" sheet locally under the press. Then no matter what, add a third leg in the front middle. You only need to worry about the area around the press; primers and books never stressed a bench !
• Don't discount a Strong Mount (or UltraMount). They sit the press much further back onto the center of the bench top AND spread the load over a MUCH greater area. Without it you get into a lot of localized stress, and thus bending of the front lip of the bench. On your bench it will be easy to shorten the legs to account for the added height. Once you load using one, you'll never want to load again without one.
• Dillon recommends having the op lever ball at shoulder height (when the ram is at bottom) when you are in your normal (sitting or standing) loading position. I like standing to load, and recommend those mats restaurant workers stand on.
• You're going to want to bolt that bench to the studs in the wall behind it. Mark the stud locations or get a "stud finder".
• Consider a dehumidifier, which will keep all your stuff from rusting AND cast off heat. Buy one that can be piped to the outside and simply let it run. You'll be plenty warm in winter, and with the aid of a ceiling fan, be cooler in summer.
• You're going to want more electrical outlets, around you and above you. Putting them in now is much easier than later. Remember, anything that plugs in avoids inspection now, and allows you to upgrade easier in the future.
Hope this helps.