You’re seeing deals because the x56 models don’t have the same feature set as the x36. Mainly no FFP and different reticle types.
As for fitting, Trijicon has detailed product measurement specs on their website. The objective bell OD listed for the 2.5-10x56 is listed as 2.6”. Divide that in half you get 1.3”. You’ll have more than enough clearance with a 1.5” optical centerline optic mount.