If you check out
Rolfs Website you'll find plenty of info to go on.
Personaly in May it could be Pellet, Meat, Worm or Bread that does most damage (it was that time last year)

as although Paste works it don't normally come into it's own till June/July at Rolfs.
In May you could be looking at catching from the margins to full length (16mtr max).
Depending on the weather before hand and where you draw on the day as although it has the reputation of being an easy water it's far from it if your not on the fish.