Here is a military style grave cross for the Metallica Pinball. It has a mounting point at the back and is hollow so you could possibly install one of the leds with the extension leads. Military crosses are traditionally a bright white so best to print this in 1 of the 2 print options. Each tip is 11mm wide and tapers to 10mm and the cross is 34mm wide x 49mm high x 11mm deep. These could be mounted on the bolt either side of the LHS Gravestone drop targets or at the back on the lane guides to the pop bumpers.