Ok so the last time I got these from covers 33 I got the wrong sort- the re sealable ones which are for the lp cover etc and the ones I need are the inner sleeves which it inside the cover. What size do I need, is there a difference between PVC and polythene and if polythene is there a difference between the 400 and 250 gram versions? Or should I get the paper/poly ones? Happy for record in new inner to go straight into the larger cover and not inner into inner.