i followed anthony worall thompsons tips when i last did roast pork and it worked out really crispy and yummy.
The night before, score the rind ( using existing and some new cuts )as deep as you can without getting down to the flesh,( this allows the natural fat in the rind to come out during cooking and get the rind really crunchy ).
Boil a kettle and pour boiling water over the score marks to make them open wider.
Dry rind. Sprinkle rind really well with salt then turn joint upside down placing it rind side down on to a clean tea towel,leave over night to draw out as much water as possible.
Before cooking rinse off the salt, oil the rind well,sprinkle with small amount of salt, and cook.
worked really well for me, and was not really salty as i expected.