Since the Blue Ox 2-Point Weight Distribution w/ Sway Control # BLU82XR doesn't have a friction sway control bar you can back up without removing the spring bars.
With that being said, spring bars do limit the amount of turning clearance for a towing rig so you might end up having to remove the bars anyways just so you can maneuver your trailer properly. view full answer...
The Roadmaster Comfort Ride shock kit part # RM-2460 that you referenced would work really well in your 2019 Phoenix Shasta 370FE. As far as improving the ride quality of a trailer these shock kits do the best job so this would be what I would recommend highly. view full answer...