I personally don't think a second, third or fourth opinion ever hurts if that's what it takes to feel reassured and validated that the decisions you are making for your child are what you are comfortable with. I don't believe there are wrong decisions when it comes to this disease just different ones and I know it is difficult to feel comfortable with many of them but validation certainly helps.
I also feel that if a doctor is worth their mettle then you seeking a second opinion should have no impact on your current relationship with them. I would broach the subject with them and see what their reaction is. If they seems miffed I would point out the fact that you aren't making decisions not for yourself here but for your child and nothing in this world in more difficult nor heartbreaking. Ask if they have children themselves and what they would do in your position.
I don't know about the hospitals there but IIRC many seem to speak highly go CHOP??
Dusty. xxx