1) interesting question - sounds like one of those you get out of a Christmas cracker. I suppose so but we know that 12 months is 52 weeks meaning that a month would be 4.3333333333333 weeks. Did you know we'd added and extra second to the clock this New Year - so that may make a difference. 3 months is 12.9 weeks. I prefer to go for 90 days myself for testing - nice round number.
2) yes, but desensitisation is a psychological technique which we don't do - but certainly, you can see the whol process - or open them yourself if you prefer.