I added 1" lining inside by ceramic mud.
I left it un-shelt under sunshine, the mud shrinked and had cracks.
I re-applied mud on the cracks a few times.
Looks not good, but it works!
I cut the leg of mutton in size of 0.5" to 1" wide. Brined in water with salt and onion for 2 hours.
I light the UDS and keep it at 200C or 392F for half hour first.
I insert the mutton on meat hooks and put hooks inside the UDS for 10 minutes.
Then I applied cumin on mutton and put back hooks for another 5 munutes.
The samll blocks(0.5") are WELL DONE. and the bigger sizes (1") are juicy.
We chinese always prefer well done.