The quantity of bait you choose to prebait with should be determined by the stocking density of your water. If you are fishing a heavily stocked lake then prebaiting with a small amount of bait my not prove to be very productive.
If you are fishing a well stocked lake then I would suggest around 2-3 kgs of boilies three times a week, larger boilies are generally better to prebait with as it avoids the attention of other species such as Bream and Tench. A single fish is capable of eating a very large amount of bait in one sitting, although this will vary throughout the year depending on water temperatures. Carp are cold blooded animals so their dietary requirements are much lower in cold water conditions. In the winter it is possible to reduce your prebait to around 1kg because of this, it will only take a few mouthfuls for a carp to fill itself up and move away from the area. On lakes that hold a smaller stock of carp I would maybe reduce the quantity of bait by a kilo or so unless you know that the fish will accept large quantities of bait without shying off them from past angling pressure. Try to use a good quality freezer boilie such as Mainline Cell , Nash Scopex Squid or Richworth XLR8 .
Particles and Pellets
If you choose to bait with particles and pellets on a well stocked lake I would up the amount as particles are cheaper and they will recieve a lot more attention from nuisance species. Maybe 10-15 kg per week baited every other night. If you are using tiger nuts to bait up with then please be aware that they are not very digestable to carp and are best used in small quantities. The same goes with what I said above about water temperatures and food consumption so alter your quantities accordingly. It is also worth baring in mind that smaller fish are more able to eat the particles and pellets you are baiting with, so increasing the quantities where large numbers of nuisance species are present maybe required for the carp to get a look in. Otherwise the carp maybe seeing none of your bait and are unaware of the area you are trying to create.
The quantities mentioned above are all just guidelines, each lake, stock and situation is different so go with what you think is best but bare in mind the factors I have mentioned. See also Part One - Part Two