Was a bit of a guess Richard. I think generally the northern hemisphere timbers are softer than Australian hardwood. When I restorered my Fordson WOT there was one small piece of timber remaining on the body which I tried to match. The only thing I could get on my budget at the time was 7/8" baltic pine from recyclers. It was some ridiculous price being highly prized for heritage building renovation so I opted for cheaper used pine floorboards and other scraps. (bought my own patina)
I had an old retired bloke at the time who milled timber for a hobby and he dressed it all to spec for me.
Too many machine shops can't be bothered with us fanatics these days so I was happy to find Nigel at Streamline Timber.
Problem these days with the exhorbitant cost of timber is it becomes a very expensive part of a restoration especially with the amount and diversity of sizes in some of the older english vehicles.
I think the Ford/Marmon Herrington gun tractor took about over $2000 worth of KD hardwood and I got that milled to spec as a favour.
I've also got a timber body to rebuild for my Diamond T in the future!!!