WD25t with cheaper tweeter

Hi,
After then years away from diy stereo (previuous efforts were from kits so I didn't have to design anything. I've decided to build a pair or 'keepers for life''. Decided on the World Design's WD25t, but with cheaper tweeters. The originals and the EX updated version are £250 each. I'm looking at more £40 to £100. The Seas 27TDFC seem at match as they reach into the lower frequencies needed for the xo with the Seas A26RE4 10" driver, though the tweeter is 6 ohms, whereas the driver is 8, so not perfect. But neither was the EX's Millennium tweeters, also at 6 ohms. I don't know if it's a big deal in designing a xo, but I imagine that having drivers with the same impedance is a good start.

Has anyone experience with this build using cheaper tweeters? I have no idea how to design a xo, though I am learning during this pandemic.
In fact if anyone has any advice or opinions on the WD25t speaker, please leave a comment.
Also, has anyone paired these speakers with a low watt (6/ch) amp? My current old Tannoys have an spl of 89dB, and my Bottlehead SEx amp can give an almost decent volume @ 2w/ch in my smallish room. So basically, what's the spl of the WD25t and do they sound good?
If anyone has alternative suggestions for speakers builds, I'm all ears.