I'm building a 78"T x 42"W built in cabinet. The plan is double doors, each 73T x 19W. Doors are shaker style with 2-3/4 stiles and 3" rails including a center rail for stability and 2 panels. I haven't settled on the rail/stile thickness....13/16 or maybe 7/8. All components are solid vertical grain fir which has been stickered in my shop for 3 weeks in a dry climate. Doors will be finished with 3 coats of Arm-R-Seal on all sides. My method is to apply finish to the back, flip it over onto a nail board and immediately apply finish to the front. This seems to be the best way to avoid warping from uneven finish application.
I've build similar size doors previously, paint grade with maple stiles/rails and MDF panels and had no obvious issues with flatness after installed.
I have little experience with VGF, and while quarter sawn wood in general is more stable than flat sawn, I'm concerned that at 660 Janka, VGF may be more prone to movement than harder species.
I welcome any insights or suggestions.