Well if you have not already purchased a set. Perhaps my two cents can be of help. I have worked with some of very finest loudspeaker designers over the last 15 years or so. And they all chant the same prayer about dome tweeters. Now before I go on I must agree you need to first figure out your xover point and decide if your going to use it in a two way vs a three way. Why? because the chant I am referring to is that they all prefer a smaller 19mm or 3/4" dome vs the larger models, why? Because of dispersion all large dome tweeters beam as they go higher in frequency whereas the smaller siblings offer significantly better imaging!!! Now, whats the trade off, there always is, in this case typically its the fs of the tweeter larger 25-32mm tweets go lower hence potentially make easier xovers with midbass drivers. They also handle more power. So, how do you deal with issue, simple. Use a wave guide (not a horn but a shallow variation) a wave guide will need some mathamatics in order to optimize but its fairly simple. You can also buy them from MCM or Parts express or mill them right into your baffle. So what does it do? it lowers the resonance point of the tweeter and increases its sensitivity so now you can use them in a two way without having to worry so much about ragged response curves of the woofers. In a three way you can get increased SPL and better loading. Now which ones to buy, hmmm that depends on a few things mostly money, there are lots of great tweeters. My fave is Hiquphon, or if you can find real Dynaudio D21's, as well as others. If you want to experiment with waveguide Peerless of India makes on but its 26mm but still works much better then typical 25mm+ tweets due to the waveguide but I have not seen them for sale you will need to search for themhttp://www.peerlessaudio.com/products_details.asp?id=50. As well the other is SEAS new DXT based 25mm. But I firmly believe a 3/4" in a suitable waveguide would do much better. Hope this helps.
Guru
Guru