Primex,
you're confusing topical spironolactone with oral spironolactone...
A combination of Propecia and oral spironolactone (in doses at least about 100mg) is asking for gyno... One of our favorite posters, Socks, uses this regimen. However, he claims to have no symptoms of gyno.
As for using Propecia, the risk of developing gynocomastia is something like less than 1%... I think it might be .02%, but without looking it up, you can bet it's pretty low.
Using topical spironolactone is safe to use on the head... it is metabolized locally and has no systemic absorbtion... Supposedly, there might be traces of spironolactone in the body after application of the topical-- but it's so incredibly low that it's disregarded.
Sorry for writing so much.
In summary, the use of 1mg Propecia and the application of topical spironolactone to your scalp contains a VERY MINIMAL chance of developing gynocomastia.