Thomas, I'm sure you're familiar with the N333, but if not, here's a couple of pics:
They are the boxed and potted types. There is considerable work in taking the boxes apart, melting the potting compound, changing out the caps, and then putting it back together to preserve the original cosmetics, especially if one is going to try to put in new film caps to replace the flatter ovals - there is precious little room under the protective grille in the OEM form.
The reason to build new and preserve old as is is because the oem crossover is still very valuable by itself, even moreso with the attached wiring and L-pads, to collectors and restorers who value the original design. (I've seen the N333 go for as much as $700/pr). If I was going the modded crossover route, I'd go with new boards and/or box, and build to my heart's content, especially because it will take up much more room, maybe even two layers thick if you want to conserve space. As for CC version is better, haven't heard or seen anyone do the Pass design but I know some have.
OP, google L300 crossover, images, and you'll see a bunch of DIY versions to give you ideas about it, also, CC L300 will get you some additional. of course, be prepared to spend a bit of money, it will be well worth it.
IMHO, I'd also be looking to refresh or renew your LE85 diaphragm (but reservations about breaking a red wax seal), look into new aluminum OEM JBL ($$$$), OEM Titanium but somehow get them aquaplas coated, or switch to Radian AL with mylar suspension - but again, may require crossover tuning with the last one.