I am using Retumbo with the 115 Berger VLD at 3200fps. Not awesome velocity wise, but I have lost the urge to tinker as this load is superbly and consistently accurate.
I also tried Magnum and it worked well also, but not quit as good as Retumbo.
What's "not awesome" about 3200 fips? Shoot, I would be giddy about that. The velocity of the max load of Retumbo and 117gr slugs on Hodgdon's website is 3079. Your load of the 115 VLD at 3200 is a long-range, flat-shootin' monster. Them UP cedar eaters better watch out for you!