I have the BMW tool and it is slightly big as well, you really need to get a prybar against it to get a enough pressure to get it started. The pry bar idea works well to press in the new seal as well.

Edit: Actually it was 2 pry bars so that it would be even pressure. I've done 3 like that and has worked well but for sure it would be nicer if the removal tool was a hair smaller to bite into the seal.

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1988 325is (purchased new) sold
2004 X5 3.0 2005 X3 2.5
2008 X5 3.0 (new to me)