Depending on how much the element of surprise matters to you, there is value in discussing it together. In my case my son turned out to be a big skeleton dial (and manual movement) fan which I would have never suspected. Doing the research and the purchase together was a great father and son bonding experience too so I have no regret.
In your selection the GO would definitely be the least common sight but considering his size I'd go for the IWC if it was me. Keep us posted!