A: The should as long as you are just covering 4x4 posts they are a pure white.
A: No, it can't be painted.
A: Fits well over a nominal 4 x 4 post. I can't answer for the post base.
|Name||4 in. x 4 in. x 45 in. Vinyl Bagged Post Sleeve||ArmorGuard 4 in. x 4 in. x 95.5 in. White Composite Post Sleeve||38 in. Vinyl White Railing Post Sleeve Kit||4 in. x 4 in. x 108 in. Composite Post Sleeve|
|Features||UV Protected,Vinyl Coated,Water Resistant||Prefinished,Water Resistant||Prefinished,Water Resistant||UV Protected,Vinyl Coated,Water Resistant|
|View Product||View Product||View Product||View Product|