I second not using very nice/expensive fabrics with Peter for your first few suits. Now that I have sorted out my pattern with Chan, I find myself not even wearing the commissions I had made with Peter. If Peter traveled, I'm sure I would have sorted it out by now. When I do make a visit back to HK, I plan on spending some time getting my pattern right with him. That said, he has some decent cloth, like Slew said - nice linens and seersucker. When I was last there, he said he could order some cloth (at the time I referenced a navy VBC I was having made by Chan, and he said his cost would be similar to Chan for that cloth - $1,200).
I would start with one of his house cloths (~$500 for one two piece suit) and take it from there. Alternatively, my advice is, if you live in a city Chan travels to, I think it is worth the extra cost to use him...maybe cheaper than all the plane tickets to and from HK when you think of the numerous fittings you will need for future commissions (but if you really enjoy Macau, maybe I'm wrong here).
I know everyone says this, and it is really exciting when you are in HK getting a suit made, but don't go overboard - have Peter make one suit, wear it for a few months and then think about getting future ones made. I made the mistake of having him make two suits and a blazer that, like I said, I rarely wear now b/c the fit just isn't as good as the fit I've perfected over numerous fittings/visits with tailors like Chan. Luckily, the cost wasn't too crazy, b/c I started with house cloths.
Note, if you get any shirts made by Peter, it is worth the extra $ to have him "pre-shrink" it (wash and dry it before cutting it). Might take an extra day, so decide on day 1 that you want to go for one ($50 for standard shirting material) and you will be fine for 1 fitting and be able to have the shirt done by the time you leave.