You can use a round pvc fleshing beam for your hides regardless of how they are skinned Dixie. Flat or tubed. If they are skinned flat simply lay it over the beam. If tubed, slide it over the beam.
Some tumblers are used for drying furs, yes..the one you seen in my photos is filled with a resin coated hardwood saw dust. I use it to clean not dry the furs as a final step. It's completely sealed no air flow.
Tanning temperatures; Some of the chemicals used for different processes require hot water, some cool water, etc. As far as the actual room temp your operating in...it's recommended you stay at room temp 65 to 75 degrees. No lower the 65 or some of the chemicals tend to coagulate in their solutions.
