intelligently combining cabs suggests to me that someone read up on the subject and learned a little something about audio physics. it doesn't suggest that someone looked at a 410 and a 115 cab, and decided that since the 115 has a bigger speaker, it will put out more lows than the 410. that's engineering by looks.
Yes that is true.
It is also true that if it sounds good, it is good.
If someone who knows nothing about speakers and cabs put two different cabs together happens across the 'right' combination kudos to them. Some folks are lucky like that.
I would think that a 215 would be a better companion to a 410 than a 115 would...but it just depends. For myself I paired a 4 ohm 210 with an 8 ohm 115 for many years with excellent results and lots of compliments on my tone.
Nowdays I usually just run one cab (appropriately sized for the purpose) and occasionally a 210/410 stack. Just haven't needed more than that.
Joe.

