There wouldn’t be a universal ‘correct’ layout.
Firstly are we talking snooker cut and 3,5”pockets or an American 9’ table.
If snooker pockets such as a 10’ Snooker, Chinese 8 ball table, possibly Russian Pyramid, Brazil Sinuca...Etc, then I would Use the same distance from End rails as on a 12 foot using World Snooker rules. Otherwise, any ‘tighter’ and potting angles become too difficult.
If playing on a 9 foot American table then I would spot the colours closer to end rails to add some Challenge...especially the black. Spotting the blue becomes problematic as it changes the whole strategy of the game. A half descent playing would just keep returning centre table and sinking it a short distance into the side pockets.