I couldn't agree on most lids for LB's being Cedar.  I and many other callmakers use a lot of Bloodwood, Yellowheart, Beech, Maple with good success.  I would say Butternut is probably the most consistent wood for bodies, though even Butternut can change a lot in tone depending on where and when it is harvested, how dense it is and how it's dried.  Poplar also works well, but here again it needs to be a softer Poplar and most is harder than ideal for LB's.  Haven't tried Sita, but Alaska Yellow Cedar works well as does Black Limba and Sycamore.  To round the inside corners I use a dremel tool with a small grinding drum about 1/4" dia.  I used to use chisels and keep them square, but found the sound doesn't change when rounded and it's more work to square them.