I believe that the Maxxed-Out is your best bet for several reasons:
1) For me personally, the reaction from the Maxxed-out practically splits the gap between my Nexxus and my Nexus Pearl. Although I have not personally thrown a HR Revenge, I know that it is comparable to the Nexxus. Thus, I believe it will still fill that reaction gap perfectly
2) You already have a Versa at box finish. Assuming you love the reaction of that ball (and how can you not?!?), using a very similar layout will also give you an awesome 1-2 combo between the Maxxed-out and the Versa. With the same layout and both at box finish, my Maxxed-out is about a 4-2 to a 6-3 move inside (depending on condtions) with touch more midlane. With this combo, went the Maxxed-out becomes too much, I already have a ball change and move that I'm confident in making. Having that confidence in an adjustment is HUGE.
3) With your current arsenal, you have 3 asymmetrics and 2 symmetrics. Adding a Nexus Solid would give you 4 asymms and 2 symms. While some could care less, I'm a big advocator for having more (or at least the same amount of) symmetrical equipment than asymmetrical. Asymms, by nature, are stronger off of friction and are thus slightly less user friendly and can be more condition specific. Everything in the strong end of your arsenal are asymms so I think it'd be good to add a strong symmetric in there to give you a different option.
4) You said you prefer solids with surface. So why not add a solid symmetrical that is the big brother of one of the most acclaimed balls in the history of Brunswick?
In regards to your other question, I have yet to sand my Nexxxus or to polish my Nexus Solid so I can't give a personal, first-hand opinion. However, I have seen Mo Pinel say on another forum that he really likes the look that the Nexxxus gives at about 1500-2000 grit.
Hope this helps!
