Transformer Theory

[dr pepper]

That looks as though it would stand a chance at spotting, though you'll probably get 50 to 70% of the calculated power though.
Your triac circuit will need to have accurate symetrical firing, ie switch the triac at the same point on the negative part of the power cycle as on the positive, otherwise the transformer primary will 'see' Dc, which it certainly wont like, and it will get mad hot, look for a schematic that states its suitable for transformer use, light dimmers are a no no.

 

[schmitt trigger]

Information on the web is wonderful, but sometimes you require an old fashioned book, to obtain authoritative information.

The best transformer design book, with emphasis on straightforward, hands-on construction, is Eric Lowdon's Practical Transformer Design Handbook.