[Closed] Handlebar shims - do they exist, where from, good or bad idea?

As in a previous thread, I'm trying to find a shorter higher rise stem for a new bike (2009 model) which came with a 90mm 6 degree 25.4 stem, I need to move the bars back and higher, something like a 70/80mm 20/25 degree stem, the new bike has a 1 inch longer TT and shorter HT placing the bars further away and lower - same bike/travel/size but 8 years apart, but all I can find is OS stems which will mean having to get new bars too, so can I get a shim for the OS stem to fit my 25.4 bars, nothing coming up in the usual places or searches?? Or, is this a bad idea to shim these out anyway??

Or should I just bite the bullet and get new bars and stem anyway - was hoping not to start swapping/upgrading parts already but the extra stretch is giving my back a bit of gip 😕

🙂