I have never used this cast bullet. However, the Mfg web site recommends below 1,250 fps for their wax lube and do not specify for the LLA coated version. My Lyman manual suggest 7 to 8 gr of Unique as a good start poing to stay under the recommended velocity. Lyman has IMR-4198 starting at 17.7 gr at 1,592 fps. H-4198 has been a little hotter when I have used it. Ex: 18.0 gr 145 gr cast at 1,700 in 26" barrel.
Unique will not overfill the case when double charaged. Put a step in your load process to ensure you do not double charge if you go with Unique. Two load blocks, one for primed cases and one for charged cases plus a look down the neck with a flashlight is my safety process. Find a safety check that works for you and stick with it when you use any powder that will not overflow the case with a double charge.
Also, try this reloading link for more ideas.