There are 2 points to balance:
If Naz would stock them, delivery would be as fast as now with the Exo etc. Even if it would be better for me too get larger orders at a time to plan and produce there is a pitfall. Naz cannot stock so much that she could take care for the best fitting springs for an order. If she would stock 10 or 20 Speedjumper Professional....which size?? 60th, 80th? Nobody will know, which orders will come in.
On the other hand....if we produce and customize after an order the Stilts will be perfect as possible for the Customer, but it could happen, that the charge in Germany is sold out, and a customer have to wait.
I don't know the answer, i just want to show the things and how they depend on each other.
Ok, many customer have also wait on the Exos for weeks or month, and when the stilts of the right size is sold out, we have the same problems also with cheap stilts.
Here for our Speedjumper customers, we re-assamble the stilts (also the cheap ones) to fit the best spring size, but that is much work.
A solution for Naz could be, to stock the base SJ Stilts and re-assemble the right Springs accourding to incoming orders. But that's not the way it works in UK, if you will get the best low prices. Than you cannot put a hand on each jumper.
So I think the most realistic way would be....not to stock it, wait like you must do for a customized car (hu hu Jason ;-) ) but you will get the most perfect fitting Speedjumper for your weight and skill. The fact that we deliver two different Types of Stilt makes the facts above not easier.
About the warranty for the Speedjumper:
We gave 2 years for the whole frame including bearings. We can, because you will not need to change the bearings, because the precision. The frames are out of doubt. You can give them to the kids of your kids, if you are to old to use them some day. ;-)
The rubbers for the Speedjumper hooves are not under warranty ;-) but as I showed earlier, it's a cheap part, and you can make it more longlasting if you bring it to your coupler.
With the springs....same problem for Naz. If the springs are ok, they will also in the SJ Stilts. And because the torsion power of Speedjumper Stilts is less than the Exos Frame, they will have less problems if any.