Microwave transformer rewind. BZZZZZZZZZZ

So I finally got a chance to wind  secondaries in place of the old EHT winding .
I put on  two lots of 11 turns worked out at 9.00 volts ac on each ,dropping to around 8.5 ac with a bridge and unloaded regulator after.
Voltage was rock solid on the out of the regulator , with about 85 mV rms noise at 7 volts dc no load ,
Problem was the current draw of the primary alone causes the transformer to hum loudly , and after about a hour switched on the core was roasting hot . Stands to reason I suppose , a microwave tx has a fan blowing cool air on it when its in operation ,which is generally for short periods of time . If it was left energised for hours it would certainly overheat , never mind the roar of the lams which is loud , way way too loud to listen to music in the same room . ;D 

I made sure my new windings were well packed with bamboo spacers and nice and tight , there also made from silicone and cloth wrapped wire , the core itself is in good shape ,no rust or loose lams ,

So my primary winding itself is causing the issue , to few turns of too thick wire ,way too much energy in the core .
Looks like I'll have to grind out the welds ,strip the windings and start from scratch , even still its been a worthwhile exercise ,not quite as easy as I anticipated ,but such is life .

So maybe someone would walk me through the elementary maths involved ,

Supply 234 volts , secondary turns count 11 x2 , 9 volts ac exactly per winding ,(nothing connected) ,drops to about 8.5 v ac with bridge ,smoothing cap ,and regulator attached ,no load .  I didnt have a clamp meter but I can tell by the noise and the heat the core alone is consuming a large amount of power ,amps of current .So looks like I need to reduce the diameter of the primary wire ,maybe up the turns count 2,3 or 4 times ,and multiply the secondary turns count by the same factor ?
The LT circuit I want to run will consume around 2x 1.6A at 6.3volts from the output of the regulators so  3 amp capacity per winding seems reasonable .

If it is running that hot, I would use 125% or 150% the number of primary turns.

While you have secondary space free, wind 50 or 100 turns of an easy gauge as a bucking winding, keep bucking until well below overheat point. Then do your math again.

I found this tool ,

http://www.giangrandi.ch/electronics/trafo/trafo.shtml

makes things a bit more easy ,
Allows me to work backwards from the current primary arrangement also .

Thanks Prr ,
I will try your buck coil idea later on the microwave lump ,
For now I managed to dig up an old toroid , 0,24,36 volts , 175w core .  ideally I need two seperate windings ,one for each LT bridge and regulator .

It looks like the 0v secondary end is the last wound on , so I might try unwind 12volts worth then  split the 24 v tap so I get two seperate 12 volt windings ,
12volts is way high for my needs so I might end up  having to regulate    to 12.6 dc first then 6.3  ,I can afford large heatsinks on the regulators ,but hopefully Im keeping the transformer within reasonable bounds looking  for 1.7A /6.3 vdc per winding , the abillity to power some 12.6 volt heater chains would also be welcome maybe at around 1 or 2 amps .

Ok ,for reasons of economy Ive learnt the cores on microwave oven transformers are driven into spurious levels of magnetic and acoustic radiation because they only need to operate for short periods ,and have a cooling fan ,the hum of the primary winding of your microwave oven tx alone accounts almost all of the noise you hear , if you had an amplifier who's transformers hummed so badly ,youd expect the fuses to blow . 750w microwave ,200watt tx?

are they square-waving  the transformer core to get more juice ?