The only input I can offer is to say that these sorts of decisions are personal and the reasons behind some people doing one thing and others doing something can only be pertinent to their own situation.
So much depends on your attitude to risk - some people keep their money in a building society and some invest it in stocks and shares. Only gamble what you can afford to lose. If you go for an IR, will you be able to live if you can't get a job afterwards? Similarly for FI rating?
My own view is that I will do an FI rating first and then, depending on the market, build hours as appropriate before going for an IR. I'm mainly planning on doing it that way round because, as Flingingwings says, an IR is tough and I ain't that good a pilot!
But that's my view and you may be a quicker learner than me which will give you a different perspective!
Cheers
Whirls