Unfortunately no, I have done thin wall aluminum extrusion design, but nothing with EPDM type foams. I would imagine though that the die shape will either be larger or smaller than finished net size depending on how much growth or shrinkage there is to obtain final size.

Always . . . no, never . . . no, always . . . check your references.

Quick one I can think of is, for small parts that are less than .125"(3.1mm) in thickness that have a fully profiled outer contour you can affix the stock material to a sub plate with 3M VHB 4910 .04" (very high bond) clear tape. Just prep the material and sub plate, make sure it has no oil or dirt (scuff with scotch-brite) and the wash/ wipe with denatured alcohol,let dry and the apply tape to sub plate then material to taped surface lightly clamp or stack some heavier material let sit for 20 min. and machine away even with coolant it will not come loose. Reduce speeds and feeds by about 25% and halve your DOCs(depth of cut). Have literally made hundreds of parts this way. Slotted/drilled/tapped and profiled, and maybe lost 1% of them and that was to probably not doing the prep a 100%. To remove the parts without marking bending, fill a pan with acetone place sub plate/parts in pan and let sit 5-10 minutes and they slide fall right off.