It's probably a smaller cap than 1uF, maybe closer to 0.5uF. The cap affects the level, not the frequency response, for this particular tweeter (long story). Best would be to try a few to home in on the best balance.
The Climax article (on the Community page) shows a more developed crossover for the ST324. More valuable, look at teh physical modifications we developed which give that tweeter greater smoothness. This tweeter really wants to cross at 3200Hz, and the original Straight 8 was at 4kHz so you might augment the 8's woofer components by 25% to push it down. There is a circuit for the most recent Straight-8 crossover design under obsolete products - I don't recall that we ever sold that version, it was developed around the time the product was discontinued, and it's still at 4kHz - but it does show a Zobel.
There are a few generic domes at round 92dB sensitivity that might work as substitutes for the stock one - by using an 8 ohm tweeter with the 16 ohm woofer, you can get away with a less sensitive tweeter (the woofer array is nominally 96dB). If you can't find an exact replacement for the tweeter, then don't use the notch filter that is in the "most recent" crossover.
