Some Thee Oh Sees albums are doubles but only play 3 sides with an etching or screen print on the 4th side - Castlemania, A Weird Exits, Memory Of A Cut Off Head, plus Damaged Bug “Bunker Funk” - all play at 45rpm, better for sound apparently but a pain in the arse flipping the sides so often. Press them at 33rpm, sorted, plus cheaper to buy.
The Anna Von Hausswolff “The Miraculous” album is another I have with a side 4 etching.
My biggest pain in the derrière vinyl is Bitchin Bajas and Bonnie Prince Billy “Epic Jammers and Fortunate Little Ditties”, a double vinyl affair, one record plays 33rpm and the other plays 45rpm, tracklisting shows that you have to play one side of the 33 then the 45 then the 33. Annoying as heck if you have a turntable where you have to lift the platter up to change the belt each time you flip between 33/45.
Sometimes CD’s are so much easier.