Behold, larry signalled from keyed 4-1000A filament:


Would they still work?...I am assuming so...

Yes.

Would they run cooler?....

Depends. If the core is of good quality then they'll run cooler. Eddy
current effects are more pronounced at higher frequencies.

Could anyone foresee any negative effects?....

You may get higher than anticipated secondary voltage.

--
Gregg
*It's probably useful, even if it can't be SPICE'd*
http://geek.scorpiorising.ca