My 2cents, after buying my avanti and well aware that i was going to do a full interior,I had a good friend who was also a pro wood worker*"very key" sign on to give me a hand.
No Pics of my tear down and rebuild but remember to.
1.seal all bare edges
2.do not leave any rough edges, when you go to wrap them your seats will be more prone to splitting your New upolstery.
3.Dont make them out of soild wood, use a sandwich technic..meaning left,right and back are hollow with the addition of support bracing in between.
4.stainless steel hardware only!!!
5.take your time do it right
Best if luck!!!!