Hi Tony , there is an actual set of mesh covers available from a PE producer - the problem is you only get two mesh covers instead of the desired four.
Part Model of Poland produce a P/E set for the Jagdpanther Part P48025 - Jagdpanther (1/48) and in the photo below you can see the two larger mesh grill sets.
( €17.06 for the P48025 set )
Two possible solutions - buy two sets to get the the desired 4 screens
Buy one set and use the cunning plan of deck stowage to cover up the two non covered grill areas.
Hope this is of some help