As you may know, I'm making restoration front and rear panels for the JMP era amps. What I don't have in my growing database yet is the back panel measurements for the 50 watt 2204 and 1987 models. I've learned that basically every feature found on the front and back panels are always centered on fractions of an inch. Whole inch, half inch, quarter inch, or eight inch increments. For example, on the front panel, the knobs are centered up 4, 5.5, 7, 8.5, 10, and 11.5 inches from the left edge of the panel. Sometimes, the holes are not quite exactly on position relative to the edge of the panel but their spacing is always the same. So it may not be exactly 4 inches from the first knob hole to the edge of the panel, but it will be 1.5 inches to the next knob hole. Would someone be so kind as to measure your back panels on your 2204 or 1987 and tell me where those holes are, relative to each other, and then, how far down the panel the first hole is from the left edge as you look at the amp from the back? With this information I can build the artwork for the panel and then prepare to make replicas.