Ctrl+G to toggle grid on/off, also add to menu -> view -> toggle grid
Grid should also be drawn on top of everything. Otherwise it's pointless, user will draw large sprites everywhere.
Draw 2K screen rectangle at center 0,0. Will help center things. Use the sprite scale constant to configure this correctly - same case as the toggle grid, toggle for this has been added to the View submenu and shortcut has been set to Ctrl+H.