This is the intended effect - tender might be bit high - but not too apparent.
Color is close enough for now.
As a fan of the 221 - in looks and running - I have often wondered about a better-looking tender for one of (I have a very small collection) mine, and in plastic, as an ERR AC Commander has also crossed my mind, as I have no idea how to signal-insulate the original ugly steel tender.
The tender above is indeed too big - especially too tall - but I think that the look is appealing, but not without lowering on the frame. That would look better anyway - it always does. As this is scratch building, you could make a frame and mounting arrangement in any design that you like. If you use some modern low-bolster Lionel/MTH/K-Line/Weaver trucks and a basswood or styrene frame made to your needs, it should look pretty nice.
The oil fuel is odd for a "NYC Dreyfuss Hudson" (of sorts), but so is the tender shell - it's a Pennsy(!) Turbine tender. Shocking! I have a little K-line (old Marx tooling shell) tender that came on some of their low-end steamers, and it is actually NYC in basic design. I may try this lowered if I ever get to it.
Keep at it. I like your intentions.