a good technique to work with fascia and keep render-time is ;
simulate your fascia -> I don't create a cache juste write an alembic with the substep of my solver.
when my simulation is over I load my alembic in a new scene duplicate my first frame and put my alembic fascia as a blendshape to my duplicate object.
then at the first frame I add a deltamush flood it to 0 on the full modele and paint only the interpenetred area of my model. It give a pretty good result !
I can also paint corrective post anim shape with the sat script or repeat the deltamush technique more than one time.
then export to alembic with substep as 2 or 3 and decrease the size of the alembic file (not tested this part for now)
and at the end : VERY NICE MODEL -> WAHOU