hi stacey! do you have a photo of the ceiling?

Dry wall not up yet so not sure if this helps.

how much more expensive are the 4" versus the 6"? Not sure which ones you are looking at.

When you buy the standard multi-part recessed lights (shell, insert, trim, and bulb), it seems like 6" has a better price point. However, they now sell complete low profile LED units that don't even require a housing.

The entire low profile light is one piece that has a junction box on a short wiring "leash" You just put the right size hole in the ceiling, connect up the wires to the box, and pop it in. The catch is that since the trim is part of the light, there isn't as much variety in styles and trim. Some examples of 4" kits below - and when offered in 4-pack or 6-pack versions they are even cheaper per light.

https://www.homedepot.com/p/Globe-Electric-Designer-Ultra-Slim-4-in-White-Integrated-LED-Recessed-Kit-91207/303240039

With angle adjustment: https://www.homedepot.com/p/Globe-Electric-Designer-Slim-Directional-4-in-White-Integrated-LED-Recessed-Kit-91222/303240027

Bruce

We generally see 5" in our area since most people are using LED these days. Standard can ( fits 5" or 6") and a 5" LED insert. There is a discernable difference in a 5" and a 6". 4" are generally too expensive to justify except for maybe some specialty areas.