The medium height rings should be tall enough as long as you have a standard barrel contour (not a bull or target barrel). The highs are the safe recommendation especially if you are going to be installing flip caps or any other accessories to the end of the scope.
Medium rings should accommodate your scope just fine.
MPN: HC740735 would be the appropriate fit.
No, these Browning X-Bolt rings are not compatible with Savage models.
Yes, these will work on any caliber X-Bolt rifle.
The Talley X-Bolt Hels Canyon Rifle Scope Rings are not compatible with a picatinny rail. They are designed to mount directly to the receiver of the X-Bolt via the included hardware.
I recommend using the high Talley X-Bolt HellsCanyon Rifle Scope Rings for that scope.
Because of the 50mm objective lens, the High height rings would be what I recommend in order to allow for clearance from your barrel. Medium rings may still be too low and would not allow you to mount your scope.
To mount the Vortex Viper 2.5-10x44mm scope to a Browning X-Bolt HellsCanyon I recommend using the 0.715" Talley X-Bolt HellsCanyon Rifle Scope Rings. These are model number HC750735.
These Talley X-Bolt HellsCanyon Rifle Scope Rings are designed specifically for the Browning X Bolt HellsCanyon Rifle and will not fit a Bergara Highlander. You will need 30mm rings for the Viper Vortex HST but the exact rings will depend on what scope base you are using. If your scope base is a picatinny or weaver rail the rings located at the link below will work. The medium height Vortex Pro Series Rifle Scope Rings should work. At the other link is a compatible scope base for that rifle.
https://www.opticsplanet.com/vortex-pro-series-30mm-riflescope-rings.html?_iv_tube-diameter=30-mm&_iv_ring-height=high-1-dot-26-in,medium-1-in
https://www.opticsplanet.com/leupold-backcountry-cross-slot-rem-700-sa-1-pc-matte.html?_iv_parent-gun-model=remington-model-700&_iv_gun-model=remington-model-700