Hi Roger. Summer fruits are best mixed, imho. 1.5 to 2 kg of fruit to the gallon, not more than half of them raspberry, not more than 1/4 blackcurrant.
Although, single fruit wines are interesting - strawberry works well (apart from the pulp and the clearing), but a mix gives a nice balanced rounded flavour.
You can reckon they only bring about 100g of sugar with them, give or take, so use 8 to 9 hundred grams of sugar.
A few ways of doing it, but one is: a gentle mash and mix with the sugar then strain a few days later to FV. Yeast can go in at the beginning or when you strain.
Usually want pectolase. I usually go with a red wine yeast.