'Amateurish?' - no way. Mike Barrett the master forger 25 years later and it's still around. Hitler diary - 6 months.
I'll leave everyone to their comfortable certainty
To be fair, it's not so much the skill of the forger as the effort into analysis that is evidenced here. The world had a vested interest in the Hitler diaries. Nobody really gives two turds for funding a comprehensive testing of the Maybrick diary...or is willing to put it to the rigors of testing.
Let all Oz be agreed;
I'm Wicked through and through.