HD210-130 Back Panel Dimensions Needed

Hi, I see requests for the dimensions of the head (upper) back panels needed. I have one missing from my HD210-130. I have tried to find rear photos on Google, to interpolate the dimensions from the known ones, but the photos are all "Keystoned" and not proportional.
Does anyone here have the dimensionas and such, or could email me a tracing. I know it isn't necessary to have, but want to restore it as much as possible. Also a suggestion for which black Tolex to buy for this new panel that would be the best match for the Music man's.

I have a 210-65 for measurements if they are the same. What is the width of your chassis?

The opening is just shy of 23", so maybe 22 7/8" -ish. There is another posting above, I now see, but he has 22 3/4" for the size of the panel. I'm not sure if that is acurrate or nominal?

I'll measure tommorrow and see what mine is.

The thread above about rear panel dims is probably the ones I need.

While I'm at it. What are the little metal counter-sunk pieces in those panels? Are they washers, or an special insert?

They're 'soup bowl' washers. You can use finishing washers - they may not be the exact shape but they do the job.
Sincerely,
Lars Verholt

Thanks. I have checked around local fastener suppliers on line and it seems they are available here. Some call them countersunk washers. I'll have to go and see them in person to find the right size, or closest match. They are good for general uses too, as they prevent countersunk screws from spreading and spliting the wood when the holes are close to the end of a board.
Waiting now to see if a friend who has piles of wood cuttings, has a piece of nice 3/8" plywood for the panel. I don't want a big piece from a lumber yard I think I'm going to replace the grill cloth, as it has a stained spot, so will get a piece of Tolex to cover this new panel at the same place. It's like restoring an old car. You want it to be authentic looking