I would try Reloder 17 and work up from 40 or 41 gr to 43.5 gr. Watch for pressure from 42.5gr and up. I get pressure signs at 43.5 gr with a 120gr BT, but that load is still sub book max. Max in theory is 44gr, but I can't get there with mine.
Depending on your barrel length etc, you should exceeed 2900 fps, and you might get near 3000 fps if you have a 24" barrel.
I use N160 on the 123gr Scenars, you'll find the Viht/Lapua published loads are very conservative but provide a safe start.
I just used them to benchmark the rifle's accuracy and got good results with mild 42gr loads and Nosler brass. When I switched to Lapua brass they weren't always obturating properly.