Hi Chris,
If you are not butchering the pigs yourself and I guess you would not with 6 pigs it would probably best to discuss what you are planning with your butchers.
I (we) have just buchered two pigs and have a fairly good idea what to do. This took me and my wife probably 2 full weekends but we also made a lot of processed products ( black pudding, haggis, suasages, bacon and ham). They were two Tamworth gilts at 9 months, probably weighing around 70 kg each (carcasse weight) fed on foraging and sow nuts.
I will list what I have done with all the bits, this might help you but it also depends whether you want to cure your own hams or mainly sell it as fresh meat ( i.e. not cured). it is from memory but should give you an idea what you could do. I am not quite sure what you mean by most cost effective, the most expensive products to buy are processed i.e. sausages and ham. You can use most of the pig but I doubt you make a lot of saving as you will have to pay for an abbatoir and most likely getting the pigs butchered.
Head - made into brawn I cut of the cheeks separatly, rolled them and braised them and had them as a cold meat. I do not think you could really make sausages from the head meat or at least not very much. A lot of the flesh on the head is actually fat or at least on the Tamworths I raised.
Shoulder- One half made into a picnic ham, the others mainly went into sausage meat.
Loin- Cut into pork chops , tender loinvarious steaks
Belly- rolled belly pork and streaky bacon. Also produced a fair amount of ribs
The belly also produced some of the fat meat for mixing with lean for sausages.
Legs- Trotters and hams. One dry cured ham and three wet cured hams used for boiled ham.
Fat- I rendered all of the unusable fat as lard.
Offal- Liver, lungs and heart went into haggis. Kidneys are still in the freezer.
Blood- made into various black puddings.
Kind regards,
DD
PM me if you want more detail