Okay Plekto, I can't help but wonder after the many, many post of advertising for Winds101 if you are Liz herself? Not that I object at all, just curious is all
I think that the silver plated head on the student Yamaha flutes are just as good as the solid silver Yamaha heads. It is not the metal that makes the difference. I do like the 500 series better than the 200 series and I think it would be a more wise choice to upgrade to the 500 or up series and put a handmade headjoint on that one. Just not a Yamaha headjoint.
There is nothing wrong with putting a handmade head on a 200 series, but expect to pay $1000 and up for even a used one. If it is priced for only $450-$500 and it is used, there is a reason for it.
<Added>I should also add that of course you should definitely try out headjoint before you buy as the Powell headjoint may not be for you. You can't always go by what others may like.
As for marching with the flute, just keep the original headjoint and don't march then with the handmade headjoint on it.