Here is the latest update on the subject:
To minimise the fine pulp, the sultanas should be coarse minced. A manual (non iron) meat mincer is fine for small (250 g) quantities and an electric one for bulk use, provided the fruit has been mixed with some warm water to soften and lubricate it. Don't add sugar yet. Pulp fermentation in a bucket with yeast, nutrient and pectolase is best. After 3 days skim the floating pulp with a sieve, strain through a straining bag, discard the solids and return the liquid to the bucket. By this time most of the sugar etc. in the sultanas will have been extracted into the liquid. Now add the sugar, fruit juice etc. if required, as per recipe.
The next day, fine pulp will rise to the surface. Skim this and then put the must into the demijohn. More fine pulp will settle and then go into 'lava lamp' mode. Once it has settled down, stir it up and it will settle into a firmer and thinner layer. When the sg is down to 1010, rack and leave the must to slowly ferment to dryness. Allow the wine to sit on the thin layer of yeast for a couple of weeks before racking, stabilising, fining and bottling.
The important principles are that prolonged exposure to fruit pulp degrades the flavour but the reverse is true for a small layer of dead/inactive yeast.
Sultanas have a 73% sugar content, so 1.5 kilos should make a gallon of pure wine of 12% abv without adding sugar. However, a more interesting wine can be made with the partial substitution of other fruit/juice/nectars/flowers/honey.
