I do not have any hard numbers for Richards 30 cal bullets yet but this spring I will be testing the hell out of my 300 Allen Xpress and 300 Allen Magnum and will offer all ballistic data I come up with here on LRH.
As far as estimates on BC, for given bullet weights you will see similiar BCs to those with the Berger VLD bullets. In some cases slighly less, some cases slightly more.
The real advantage of WIldcat Bullets is the range of bullet weights. I know Richard makes 30 cal bullets from a 68 gr HP flat base up to a 290 gr ULD RBBT. Thats 222 grains of bullet weight options to pick from, no one else offers anything close to that.
You can contact Richard at firstname.lastname@example.org
He is a hell of a guy and a great bullet maker!! He can be a bit hard to get ahold of sometimes though so be patient, he will get back to you.
As to the question on if I would shoot Wildcats or Berger bullets. Every one of my Allen Magnum or Allen Xpress rounds were designed around specific Wildcat Bullets and that is all I use in them for the most part. That is not to say some specific rifles will not prefer other brands of bullets because that happens with all rifles but I can tell you every one of my personal Allen Magnum rifles that have taken big game have used ONLY wildcat bullets and will continue to do so simply because they offer ballistic performance above anything else out there in many caliber choices.