That sounds like a lovely rifle and also a fun adventure.

You might have already done this, but I'd recommend getting a copy of Wright's "Shooting the British Double Rifle" if you do not have a copy. It is very helpful for getting an old double rifle to regulate. I've just got an Alexander Henry 500BPE and his book has been very helpful in getting it to regulate.

Beyond that Sherman Bell, Ross Seyfried and Frank Findlow's articles in the DGJ are great further reading.

Please post pictures when you can!