Kunes don't need the extra protien levels found in fattener pellets - they'll end up VERY fat, stick with sow & weaner nuts or rolls.
The way I do it (with backfat results of around 15mm on the carcass) is to feed 1lb of sow and weaner nuts per pig, per day plus a bit of fruit and veg. There is no need to up the amount until there isn't any grass for them to graze on or you notice them drop condition, mine get 2-3lbs a day in the winter and a bit less if we have hay to feed them. If you're going through more than 3, 20 kilo bags of feed a month between the four of them you're over feeding. (but, if they have a worm burden they'll not use the food effectively and will need more to gain weight - another good reason for sorting the worm issue
)
Is there any size restriction in the abbatoir you intend to use ? If there is, you'll need to make sure they don't end up too big for them to take.
The usual for bacon is over 100Kg liveweight, but I've made bacon from pork weight pigs - it tastes just as good, it's just a bit smaller (my local abbatoir doesn't take them at bacon size
) It would probably take over 11 months for them to be bacon weight - think Beewyched's 16 month old castrate tipped the scales at over the 100Kg - practice weighing them (tape measure and a calculation in the absence of a weigh scale) and just do it every month or so to see how they are progressing.
HTH
Karen