I'm going for approx 35.5" high. I have a low couch and that height would put the tweeters at my ear level (which is usually recommended for floorstanders). eg. the top part of the cabinet will look exactly like a bookshelf AR.com DIY eg. 3" tweeter centre from top of cabinet, woofer approx 6mm from tweeter etc...

What I find hilarious is most manufacturers will make the lower end towers "shorter" to make their models through the range look bigger and justify the increase in price. If I made speakers......

PS: - don't forget to allow for feet in your tower design - these can be 1"+ if you use spikes

I like the idea of a shelf on an angle. Help break up panel resonances.

I notice with the Madisound kit they give you foam for the walls. Should you still stuff with batting / acousta-stuff? If it helps absorb unwanted midrange from escaping from the port - fine, but if it is just to make the box appear bigger for the woofer (which stuffing does by roughly10%) , I can do that by moving my partition down the cabinet.

Cheers,
David.