Unfortunately I'm not much of a madeira aficionado, in fact this is the first and only bottle I've ever tried. This is something called Broadbent Rainwater and picked it up on a whim after a lot of disappointing cocktails with Dubonet Rouge. I'm a big fan of Warre's Otima port which is very smooth, nutty, sweet and woody and this madeira immediately reminded me of Otima though not nearly as smooth and not quite as sweet.
I've been taking liberties with the Old Fashioned lately since stockpiling bitter (yes, those are scrappy's) and seeing a video from Jamie Boudreau making a wild version. Sweet, strong and bitter in relative proportion should pretty much do it. I'm thinking you can get sweet from something that tastes vibrant and complex like madeira, port, and any sweet liquor really, don't spend your sweet budget on simple or rich syrup. Rich syrup does a lot for the mouth feel with less volume. I've made this with a quarter oz of rich syrup and possibly enjoyed it a little more.
Tonight I swapped the Buffalo Trace with Bulliet Rye and added an additional dash of cardamom bitters (that rye is too sweet and needed to be cut) and built it like a traditional old fashioned and I'm finding it very enjoyable as well. The brandy I'm using is Presedente which is Mexican and hints lot of bourbon qualities, I've even put it to the pepsi challenge with bourbon fans who would swear it was bourbon.
More than you were asking, I know, but thanks for your interest. Have fun and let me know if you get a chance to try one!