Hi Tim,
If you're talking about powering a single source component, maybe 60watts consumption with 2 175va transformers, its workable. Not only will dissimilar secondary voltages allow you adjust output voltage, but the actual power draw will also radically effect output voltage because of a transformers 'regulation' which is related to its output impedance. And when one puts 2 transformers in series, its multimplicative. A transformer with 10% regulation is going to be 110% of its rated secondary voltage at no load. Put 2 in series, and you've got 21% regulation. Use one of the transformers, arse backwards, and its worse.
I honestly cannot recommend implementing a Felicia, specifically to either adjust voltage or for its power conditioning abilities. The potential benefits of balanced/technical power is minimal unless you're powering your whole system with it. The Felix is a far better power conditions, and is far easier and less expensive to build.
If you have access to multiple surplus power transformers of the same type and VA, but with differing secondary voltages, you could juggle one of the transformer's secondarys voltage, as well as the power draw, to get a specific step up or down at a specific power draw.
Sorry, but in my opinion, its not worth the effort.
Regards,
Paul