Say hey.
if you got the K down to 200ma., great. The dip is usually much sharper than you describe, but if it holds at that value, what the hey. It wouldn't hurt to keep the meter on it for a while. Gotta luv the Simpson 260 huh?
It doesn't sound like you have any heat problem to speak of. The power xfmr will run pretty hot to the touch. The fly will get fairly warm. Sheet metal will warm up from radiant heat off the hot tubes.
The hiss sorta remains a work in progress.