Solid solution for adding red dot finder to Celestron Skymaster 20x80

[elliot]

I've been looking for a cheapo solution to attach the cheap and ubiquitous red-dot finder to my Celestron 20x80 but didn't like the official clip thing that Celestron sells. Bad reviews complaining of it easily snapping, and to me, overpriced.

After much research and counting of pennies, I went for this all steel, no-snap solution, costing a whopping £6.90 (with free shipping).  From the top:

1 x 20mm Dovetail to 11mm Rail adapter. £2.69 with free shipping. 
https://www.aliexpress.com/item/20mm-Dovetail-to-11mm-Rail-Mount-Weaver-Picatinny-Rail-Scope-Mount-Rail-SA089-P15/32800225228.html?spm=a2g0s.9042311.0.0.b0d14c4dzyuqK1

1 x  Picatinny/Weaver 20mm Rail Base Adapter (used to attach scopes to rifle barrels) .  £5.11 with free shipping
https://www.aliexpress.com/item/20mm-Picatinny-Weaver-Rail-Mount-Base-Adapter-Tactical-Hunting-Rifle-Gun-Scope-Mount-Converter-Laser-Sight/32792605686.html?spm=a2g0s.9042311.0.0.b0d14c4dzyuqK1

1 x bit of thick plastic to act as a shim. Anything will do.