the arched bak veneer isnt rocket science, you just have to coerce the wood to co-operate, bully the thing!
heres what i did:
(poor pic i know, sorry)
first soak the veneer in hot water on the stove, then bend it round a rolling pin and allow to dry outside for an hour, once thats done its more or less the right shape for joining.
Then just clamp the flat part down first, then squeeze a rolling pin against the curve and clamp!