I have a 40" curved and it's more than enough.
Went with the curved as it has the floods on the side edges and the spot in the middle.
I have it angled enough to not bounce back off the hood scoop and as previously mentioned, it reflects back off signs a little too much.
Not supposed to be using it on roads, but those paved entrances into Death Valley are dark and that's where I've used it on road a few times.
When hitting the road for camp after work on a Friday they are great when you hit the trail head and it's totally dark, but really it's a luxury item. I maybe use it a dozen times a year at most. So keep that in mind when buying one, how often you going to really need it?
The other main con is it will humm and sing to you on the road. The heat dissipation fins on the back will vibrate at higher speeds so you might also need to get some rubber stripping or some stabilizers to prevent that happening.
This is the best straight on pic I have atm for the 40" curved. It's as wide as the gobi rack and adding another 12" might have it extend a bit over the edges of the roof. Never really seen a 52 in person.