Long live pinhole photography

I have heard quite a bit about pinhole photography recently and decided to "give it a go". I have purchased a plate for an EOS 600 I do not use so much now and wonder where to go from here. I intend to try it with Fuji Acros 100 which has extraordinary reciprocity failure figures so wonder what sort of exposure times I might be looking at. I realise the size of the pinhole is important but I cannot quote this at the moment.