I'm hoping that the next type of stone we build is one which can be entirely built in house by the colleges, just because we have more influence with them and can get them to throw more magical manpower at waystone creation, especially after we drop the orbs of power on them.
Thinking about it more, my preference is for something that's officially an export model (but the Colleges can manufacture in extremis), a design that shouldn't be deployed in the Empire but we'd get the Ulthuani elves to license the design, pay us royalties, and countries that needed them could buy them.
What I'm thinking is this:
Export Model
[ ] [CAPSTONE] Collegiate
[ ] [RUNE] Wizard
[ ] [STORAGE] None
[ ] [FOUNDATION] Collegiate
[ ] [TRANSMISSION] Riverine (Spirit)
This is a design that the elves of Ulthuan should be able to manufacture at scale as they've (hopefully) plenty of people who can do Wind enchanting, possibly even using different Winds, albeit one at a time, and it's not very expensive. Two low costs, one trivial, and whatever you need to pay the local river spirit.
I think the Collegiate foundation is much more politically acceptable for a Waystone design that wouldn't be deployed in the Empire, as they would be out of sight and so out of mind, rather than having a College designed enchantment manufacturing Dhar on street corners.
Similarly, being dependent on making a deal with a spirit is much less of an issue for an export design, as it's the customers' problem. Kislev seems to have a good handle on its water spirits, so I don't anticipate it being a problem for them, and I think there are suggestions that on Ulthuan the elves have decent relations with the local nature spirits. In other places like the human inhabitants of the Southlands or the East, that's the local's issue to sort out.
The big, big thing about this design is that Boney has confirmed that it could work on a boat. This means that the Waystones would be vastly easier to deploy and transfer/concentrate where they're needed. Negotiate once with the spirit of the river, and afterwards any 'Wayboats' you have along it would function. That way, if, say a Storm of Magic blew in from the north, Kislev could sail a flotilla of Wayboats up the river to intercept the storm and drain it downstream. That would create a quite fun and quite flavourful squadron, who'd probably collect all sorts of bizarre stories to tell of their adventures. The stretch goal of this would be to see if you could learn to tap into the power flowing through the Wayboats in a controlled fashion to power a battle altar so if you sent them to intercept a Storm of Magic or similar they'd be better able to fight any nasties that accompanied it. You might need to add a Cheap enchncted battery for that.