I wouldn't open with Bishop here. You want to get to GMs as fast as possible and then lay on the Throne Rooms afterwards. This is probably a board where I'd consider opening Chancellor. Try to get a few Treasuries in deck and then grab a Bishop of your own at some point because your opponent's Bishop doesn't help you very much after a few trashes.
Also, I'm not sure why you bought so many Silvers. If you want GMs, a more flexible way to get them would be TR'ing terminal coin. Like Chancellor!