Tips on repotting a Phal?

[supersheep]

So, I've got an orchid I bought last week (I've become such an addict!) and I plan on repotting it tomorrow, as it came in dodgy looking moss. I've also got another phal I plan to repot too, which I bought about a month ago and the roots are looking a bit moudly in the bottom.

So, I've read on here about how to repot, but the last few times I've tried, I've had problems after with mould on the stem and roots. I do wonder if the orchid compost I got then was a bit dodgy...

So, I'm wanting to make sure I've got it right this time! I've got some brand new specialist orchid pots - a slightly larger one for one orchid as it's got lots of aerial roots. And some orchid compost, which got very good reviews from the internet. The compost is a bark and coconut fibre chips medium, which I think is ok...

So, first question, should I soak the compost first, maybe overnight? The compost bag says you can use it straight from the bag, but I'm not sure.

Second, I know to wash away the old compost and remove the dodgy looking roots with a sterlised knife/scissors, but should I soak them in anything after I've done that? I seem to always have problems with mould (and I am trying very, very hard to not overwater my orchids!). I can't really get hold of much in the way of fungicides, or that Physan 20, but I have cinnamon powder and 6% hydrogen peroxide. I also have some freeze dried kelp powder, which I've heard is good for orchids...

Thirdly, how high do you put the compost up the plant - or should I say, how deep do you bury the stem. One has lots of aerial roots, which I think I'm ok with putting in the pot. The other has lots of short roots coming out just below the flower spike (it's still got 2 lovely flowers on, but it's the one with the mouldy roots!) Then there's about 1/2 inch gap before you come to the base of the first leaf (it's lost 2 leaves recently, they were small and yellow and I think it was due to age?) So would I be ok to bury these roots and the bottom of the flower spike? So the compost reaches the bottom of the lowest leaf. Would this make it too susceptible to crown rot or anything?

Ok, final question, should I soak the orchids in water before repotting too? And if so, for how long? And before or after I use anything to help with the mould problems?

Oh and is there any other tips on repotting? As I said, I've read through these boards and already learnt so much, but my bad experiences with repotting before have made me paranoid!

Thanks for the help!