I'd sure stick to something more robust than a BT for the 300Wby. My experience with the 270Wby and 130gr bullets (hustling along at 3450fps mv) is that stout construction is the order of the day. I've worked with E-Tips and bonded core stuff in my 300Wby, as well. Check out the Nosler Accubond, Hornady Interbond, and Swift Scirocco if you're set on a polymer tipped bullet. I think you could easily use a 150-165gr Nosler Partition, as well, with good results. If you decide to shoot a monolith (E-Tip, TTSX, GMX) I'd stick to the lighter weights (150gr would be my choice) and find an accurate load.
Good luck! Oh, and overall, there's no such thing as too much gun for medium to large game. I know a guy who shoots antelope with a 416'bee, just because he has the rifle and can make the shots. Plenty of dead antelope, and moderate meat damage.