Six inches is sufficient to rotate a box 90* and you don't want it to look like the cover plate barely fits

If this is an inspiration pic it has drawbacks. A gas cooktop with a window behind is different than a window behind a sink. Design alternatives should be investigated. No code requires wall outlets behind a range or cooktop. That picture shows poor design. Horizontal outlets below windows mounted close to the counter don't compute structurally because of the framing to support the heavy window. Maybe a popup outlet in the counter surface like on an island is a choice. Best Pop Up Outlets, Hidden Kitchen Countertop Sockets – Kitchen Power Pop Ups

Consult with your architect, electrician and builder.

I sure hope that pic is not your space tha cooktop in frontof a window is just all wrong. Ia gree 6" is all you need for the electrical and if you post a pic of your space gets real answers. I assume the sink is in front of the window so I would want that window at least 6" above the counter to hopefully control some of the splashing

Yeah this seems illogical. Is your sink under the window? Why would you need outlets above the sink?

If you don't mind cheating, I built a temporary box out of scrap materials and mounted the code required outlets, which were wired to adjacent outlets. After receiving final electrical inspection I removed the box, pulled the wiring, and finished trimming the window. The walls are 4" deeper than normal, and the granite extends back to the window frame, so we don't have problems with splashing of water on the window.

Never disclose your location.

My dad used to saw down the polarized end of the plug to fit the ancient boxes.

If you wiped down the toaster with a damp rag? You were blown back *&&^^%##@$ to the dining room....

His answer? "Unplug it first...are you dense"?

GC says 4 inches is enough, but I'm hearing here that 6 inches is better? Should I tell him 6?

For those who asked, outlets go here because code requires them. There will be sink in front.

I actually want to see your space . usually wall plugs can be done on the wall either side of the window so I need to see your plan.

The receptacles will be left or right of the sink- not directly behind it!

All kitchens have these codes - or you'd not be able to plug in a toaster or coffee maker !

Yes that's what I meant, near the sink not directly behind. It's a long counter and it's many windows. He said they are placed every 4 feet or something like that. So should I tell him 6 inches instead of 4?

Your General Contractor is telling you 4" and you want to do what a stranger on the internet is telling you instead???

We were able to put outlets under countertop.

The 2 3/4 inch cover plate ( rotated ) will fit on 4" riser

That I prefer it does not look squashed on a riser is me, not you: ) and it is also personal taste that I find a 4" riser to look skimpy.

Do as YOU like !