Altec 421-8H Series II Box Size??? Any Ideas Where To Start?

Howdy, just got a couple of Altec 421-8H Series II speakers I wanted to put in use. I was wondering what the best size box is to put them in? I would like them to be able to play to down as far as possible and flat as possible also. I know I'm not going to get any "real" deep bass but I want to get as much as possible with good power handling. I will be bi-amping these using a couple of 811b horns that have 808A drivers (with alum. dia.) and using a Samson 2 way electronic crossover that has CD horn compensation, low frequency delay and limiter. I'll drive the woofers with an Altec 9444a/sa amp and the tweeters with another Altec 9444a/sa. They are rated at 200 watts per channel @ 8 ohms. I've found the theile-small paramaters and have fooled with them in Bassbox pro software. They just don't look too good no matter what I do with them. I can get the -3dB down to around 55 or 60 hz with good power handling and flat response using between 3.5 - 6 cubic feet with the port tuned to 60hz. I do have some old 1202B cabinets I can put them in but they have a big square port. Not sure where those are tuned to. Anyways, I'd appreciate any help on these. I'll be using the speakers for "hi-fi" setup only. Thanks!

I've got 418-8H II woofers in 8 cu. ft. boxes with 33 cu. in. ports and think that they sound pretty good. Try that in your box program. In winISD pro, the response looked the best even after messing with the box and port size for hours and much better than the recommended 4 cu. ft. box it spit out on auto-pilot. Use lots of EQ, I tried 2 graphic ones wired in series which let me boost the 40hz band while cutting the 25hz and everything above 40hz. It has a nice low punch with out the 63hz boom and can definetly rattle everything in the house.

Here is the graph.
http://www.hostboard.com/forums/hbmc...2011/12/16.jpg