stang,
For most purposes Unique if absolutely appropriate in .357 Magnum regardless of what you are shooting it in. If you are going to hunt Deer you may want more velocity than Unique will safely give. So far as loads, use the same data as for revolver. As a matter of fact, many manuals will show slightly lighter data for rifles strictly to avoid extraction problems, but rarely will revolver data actually cause a problem in a rifle.
Lead and Micro-Groove barrels go together just fine provided the bullets are hard enough, lubricated properly and sized correctly for the particular barrel. If you purchase bullets use a company which gives you the option of selecting your sizing diameter, such as Beartooth Bullets. Theirs will shoot just fine. What you need to avoid "Generically sized" bullets of unknown hardness, particularly Hornady and Speer lead bullets.
Slug your barrel and then order bullets at least .001 larger, preferably .002. Don't use a Lee Carbide Factory Crimp die with bullets larger than .357 as it will size the bullets inside the case and defeat the purpose of buying larger ones. Same goes if you are going to cast your own, hard alloy, at least wheel weight plus 2% Tin, and size .001-.002 over bore diameter and everything will work fine.