tri-4 bars and bushing placement

[62fairlane]

I am working on a trianglated 4 link on my 62 and was looking at jonny joints for the bar ends. now I am told if I run a poly bush on the parallel bars they will be fine and that the angled bars only need the jonny joint on one end? I am just wondering exactly what is needed and what is gained over each option.

BTW I love the fairlane chassis....the rear suspension bolts out for easy cross bar work and the front arm mounts boltout too....almost too easy to mod