Yes for all sensors injectors etc in loom I will run separate lives for injectors ,Idle valve , air injectors , O2 sensor etc .
I have found some 2 core and 3 core shielded cable from rs components . I can get for free thin wall single cables . . the price of raychem is a bit high . especially as in want to build 2 looms . and most aftermarket looms are not built with raychem . but undo know a couple of aircraft engineer so I will see if I can source from them .