Be careful with bonds suits as the sizes are not accurate. I would be inclined to buy 000 bonds suits and take it from there. Just buy a pack of 3. Dont forget you get heaps of clothes from relos so dont go to mad other wise you end up with to much.
With DS he is a size 00 but i have him in 0 bonds suits, always go the next size up to what you want. Thats with all clothes made by them. Very frustrating but once you get the hang of it you wont waste so much money.
Good luck