In-game, windowed. Quit. Edit %USERPROFILE%\Documents\CAPCOM\RESIDENT EVIL 6\config.ini. (But backup first! You may want it for skill points menu.) Resolution=####x#### (yours. + border = borderless), Aspect=OFF. Read-only. ShiftWindow (same nums & to position). Screen remembers on reboot.
(PLP screenshot with bezel effect)
In-game looks good, but some oddities: Some rendered cutscenes that are single-screen are left justified. Main menus are massive, but all usable. Menu complications:
[1] Quit is off-screen, can be scrolled to, has visible tool-tip, or just use Ctrl+Alt+Del.
[2] Skill points menu (used between game chapters. Can easily access via Play Game, Campaign, Skill Settings). Top & bottom is cropped off. Safest & easiest to shut down game & paste back original config.ini to pick skills. Can be done in PLP, but it's hard the first time: Must remember where stuff is that can't be seen, points total included. To do it in PLP, pressing Enter will select slot 1 (off screen top). Then select your skill (seen or by tooltip). Then must Left-Arrow to Yes (off screen bottom). Could try Flawless Widescreen &/or Widescreen Fixer to fix menus, but these failed me. Could try hackin FWS lua file, not tested.
View guide for general help with the instructions.