The V-PFB/482XX B6BLE/Crusaders did occasionally venture onto what was the 90 and the 88/89 before that, depends what specific bus was swapped IIRC. Weren't they new for the 20/21/22/73 originally? I remember Bath having one's that would eventually end up at Buses of Somerset and not being particularly fond of them, the hard low back seats did not help.The B10BLEs were a really good piece of kit and I didn't mind the B6BLE (Wright Crusader 2, which First Bristol used to operate on the 20, 51 (and 90?) all now defunct routes) either.
In Bristol I found the ALX200 to be OK too.
Also(slightly off topic here) I seem to recall allocation swaps were pretty common for Darts M532 FFB and S725 AFB to be swapped with one another around this time. For example M532 FFB could be on the 90 whilst S725 AFB could rock up on the 51/52 in it's place. Made for some interesting variety as a bus enthusiast in South Bristol! The ALX 200 bodied darts were my absolute favourite as a young enthusiast, V734 FAE was the one I'd look out for and try and ride the most!