These are the ebay websites I ordered from:

'4 / 8 ga. AGU In-line waterproof Fuse Holder',
http://cgi.ebay.com/ws/eBayISAPI.dll...3AIT&viewitem=

'Hi/Low Impedance Adaptor RCA to line'
http://cgi.ebay.com/ws/eBayISAPI.dll...3AIT&viewitem=

'24k gold Ring terminals'
http://cgi.ebay.com/ws/eBayISAPI.dll...3AIT&viewitem=

The last 2 items (above) can be shipped together.

Radio Shack carries the blue T-line connectors:
http://www.radioshack.com/product/in...ductId=2104093

Thanx for those added pointers, Carlgo! You also have a point about everything being 'squared'. It would make a difference because my cardboard constructed box is just hitting both of the lower corners of the (upper) subwoofer enclosure's cavity opening.

I'll go Home Depot to get the (2) 4x8 MDF sheets, (3/4" = USD $26.21, the 1/2" = $19.21), and Spatz screws....I don't have air :-|, so I'll have to settle for a powered down variable drill with a screw bit(?) or buy a power screw driver.