Sorry for the silence. We're still working on the steel string supply issue.
This is the part where we need someone to explain which size steel strings we need, and how much of each size to string a piano.
We've tried several places but it's not proven fruitful. Last week we called up Mapes Piano String Company in Tennessee. They are piano string experts and have very kindly offered to take a look, so we've sent them a sample board of all our steel wires in the hopes they can give us some accurate measurements and advice - and, ultimately, supply the wire.
The reason it's taking so long is that to send an A4 envelope next-day delivery with UPS would have cost us over FRW 50,000 (£50, $65)! Meanwhile, at the post office, the same letter costs FRW 2,000 (£2/$2.60) but takes two weeks to get there.
So, industry is on hold for a while until the letter arrives.