If it were me, I'd work on filling all those holes so you are working with a blank canvas
Does that piece come off? If it does you're way ahead of the game since you can work on it with it upside down. If it doesn't the I'd be inclined to just cut the whole top area out and piece in a new flat section that you make up from cloth, or cut from an old hatch cover. Ditto the old helm hole.
Alternately a sheet of aluminum, painted black and shaped to fit the whole top would be nice too.
When I did my latest console I put stainless steel trim bezels under all the gauges. Really makes it look sharp. These come in anodized aluminum colors too.
One trick I learned is to lay out for your new gauges in Adobe Illustrator, Photoshop or something that lets you work out several layouts before taking any cutting tools to your console. Once you get it perfect you print a full sized copy and use it as an overlay for starting your pilot holes. Don't forget to put tick marks in the center of your circles.