Jan has simple pretty much cornered.
The bricks belong where you wont ever run conventional. If that track doesn't exist, don't use bricks, just use transformers. The brick is just a compact easy to hide item. Thats important to some folks. It also keeps you from needing to touch a throttle handle... also important to some folk. Their goal is often to seperate themselves from the convetional world as much as possible. Be mindful of this as you heed advice on command; not everyone will be thinking about conventional operations being side by side.
The only real difference on power is a brick output isn't variable. ( But there is prudence in checking the actual output on transformers to make sure you don't exceed the 18v command voltage max. There are a few ways to ensure a bump to full throttle only gives 18v. Some may put out over 20v and for sure if the transfor.ers whistle circuit is engaged)
The ZW&ZW-L are two different animals. With a lot of electronics on the line, the ZW,KW etc. can use a breaker update (inline magnetic vs thermal) and TVS addition, to speed the disconnect on shorts and sponge up any voltage spikes (TVS) .
If the ZW is a ZW-L say so. It has features not seen elsewhere.
How big an area? A run around you? Or you in front of a bench? (even a big one) (This is for wiring.)
A ZW (or KW) can channel all the power into one throttle and equal a couple of bricks on one line if you had plans for a huge ABBBA with 5-7 motors and two dozen lit passenger cars or something. A KW handles my12x15 ceiling loop pretty easily. A Z (prewar ZW in a different case) laughs at 12x15 and grades to boot. As you suspect, you have a ton of power there.
To step up power from Jan's version of Z+command, Using one throttle on each of the two transformers(zw&kw), for two loops would max the watts available to the tracks and retain varibility on both lines too. (if thats a goal.)
Another option is simple toggles to swap which power feed goes where. (transmission of the commands to all track all the time isnt an issue. Only the 18v non varible is an issue.)
To avoid toggles there are command accessory controllers so you could do switches by remote. (ACS?... too many fancy buzz-word names I never bothered to learn. That kinda crap puts me to sleep, lol.)
You may want to search YouTube to see what Lionel has posted there too. While you're at it, if you use two transformers, bricks, etc. watch the "phasing of two transformers" video. It's a must. If not, you may want to watch anyhow. Some deeper electrical basics are nicely covered by Mike and he isn't boring either.
