what would you recommend I use and should I coat the brightened brass when finished?
A variety of choices, eh? Since this was posted in a "restoration" category, and the clock is pretty old, restoration would maintain the original look, including the normal effects of time passing. I don't think much was lacquered in 1890, so it would have tarnished and dulled naturally over the last 130 or so years. What condition is it in now? If the pendulum bob has an even-looking patina, I would suggest leaving it alone. Hard to do though.
If it's super dark and gritty from isolation and exposure, you could use some wax as discussed. If you don't rub too much of the patina off when putting on the wax, or "make it even" by hitting only the darker spots a bit more with your thumb, that may help a little and it may not get much darker over time. This can also protect it against future fingerprints from normal oil on hands, etc. when you play with it, so it's something to consider. Same thing generally goes with the movement: just clean is the goal, no more than that; only polish the pivots. Also hard to do.
If it's partially lacquered, meaning it was polished by someone then sealed a few decades ago, but some of that has since flaked off, and some not, then it will have "black streaks" against polished brass. To me, this qualifies as a previous "repair" gone astray. I would strip, even it out, darken if needed and then let it tarnish naturally. Same thing if it took a hit, etc. If you later decide you went too far brightening, you can put back maybe 10-15 years or so, but once polished smooth it will take another 130 years to return to where it was. So, if you want it to pop, how far to go is up to you, but less is probably better? ;-)
There are fancy chemicals that will re-darken brass, and home-brew solutions with heat, salt and vinegar, but it never goes all the way back. This is why the PBS/A-R folks say that, and why coin collectors won't pay much for coins that have been cleaned or polished?
