If you can get some you may want to give Ramshot Magnum a try. I have been pretty impressed with this powder. Your limited on case capacity and a ball powder will get you more grains per volume then any stick powder. Magnum is similiar to RL-25 and Retumbo in burn rate and has been pretty good with temp changes as well, espeically for a ball powder.
It is a dramatic improvement over old ball powders. Easy to ignite as well, in fact Ramshot recommends using only standard primers, no magnums.
Load density will be more comfortable then a stick powder so there will be no powder fracturing when seating the bullets which can increase powder burn rate. If it were me I would try Ramshot again, if you can get it. I have a feeling you can get your hands on pretty much anything!!!
Just my opinion, let us know if you get that mid 7mm shooting well with that bullet. Hey, better yet, start hounding Richard for that aluminum tipped 7mm bullet!!!