Make sure your twist will handle the long 180VLD. 1/8 is needed. 1/9 may also work. I used 68-69g of retumbo and shot the fire outta the 180's.
Warning is that the bullets are very sensitive to seating depth. I'd start with two or three rounds each with the same powder. start with 65.5-67g of retumbo. Seat .010 off the lands and shoot'em up. the group that shoots the best (lowest, most horozontal... what ever your standard is.) is the one I would change its seating depth by .010.
168 shot best .080 off the lands and 180's were .010 off the lands in my sendero.
I figure you can get a load worked up in about 30-40 rounds.
I tell myself that all the time and more times than not I'm 500 rds into a new barrel before I get serious.