Personally, I don't see any reason to make your own dash mat when you can buy a custom fit one for 40 bucks on Amazon as I did. The one I bought was brushed suede and I'm really pleased with the results. I don't even really need a CPL at all with the dash mat but having both is "killer". As I've said previously I went the extra mile and spray painted my suede dash mat with
Rust-Oleum Flat Black Camouflage Paint to eliminate the slight nap in the fabric that could show up in strong sunlight and that made it extra effective but that sort of thing isn't really necessary and is more for DIYers and dash cam fanatics like me.
Photographic specialty fabrics (usually specialty velours but sometimes
flocked) would probably work really well but then you would have to do what @Street Guardian did which is an expensive and time consuming proposition with probably only marginally better results and diminishing returns for all the trouble and investment.
There are some velour dash mats on the market but I have no experience with them. The problem with some of the dash mats on the market is that they sometimes are made with fibers that can be shiny and you don't really find out until it arrives. I have the feeling that some velour dash mats have a sheen and if one buys one that would be the thing to try to find out before purchasing.