depends on the wood and if its soft or light in weight ,, burl has a tendency to crack around the eyes in burl so some times it helps to stabilize it don't fill cracks but helps ,, cherry burl is normally good with out but all depends some times ca will take care of the smaller cracks
and yes some woods will suck up lots of resin and others don't barely take any at all and at $1oo a gallon some blanks can get expensive ,,, on the harder grain woods I like rough turn a pot inside out that way the resin has a better chance of penetration