AHHHH, the light goes ON!
Consider this:
http://audioheritage.org/vbulletin/s...ad.php?t=11756
Can you mod 035tiAs (cheap on eBay, or maybe someone here has a pair for you to try,) to fit your DIY in-line L100 driver alignment? They play to some outrageously high frequency (27 kHz?) as I recall.
That's a far better approach than trying to boost the paper tweeters with EQ.
Also, as we've discussed before, getting down to just ONE tweeter and mid playing per side will be a substantial improvement.
Maybe try this with your 4401s:
Run a pair of your L100 woofers ONLY as "subs" with them. Make sure you get the phase correct.
Then, having stated elsewhere here that you don't like boomy bass, close the ports on the L100s with plumbers' test plugs (from the hardware store), and see if you don't like this combination even better with the boomy bass gone.
If so, add a sub crossover on the system to shut the woofers down above ~100 Hz.
THEN, you'll have a stack that actually works. (See below)
A waste of L100s using them just as subs? Find a pair of L88 cabs like these to refurbish. Same box, basically, with cool Eames moderne grilles to match your '50s phones.
[Pull the port plugs any time you want the boomy bass back....
]