The unique gifts (his mother’s locket and Duncan’s shield) seemed to boost approval much more on the console than they do on the PC.
This is for the PC version, but it should get you close on console, as well. The approval rates vary slightly from the PC. Note: I had an opportunity to play on the PS3 recently. Obviously this entire post is spoilers, so don’t read it if you don’t want to know specifics about Alistair. There are posts for other characters as well.
