6qts will do it. 0W-30 nothing else there are tiny ports that the oil needs to be thin enough to get into when cold for the cam adjusters.
Also order some German oil filters for it they have a check valve in them to protect you. Filters at the auto store don't.
I use mobil-1 in mine, $26 for a 5qt jug at walmart.
add 1/3 can of seafoam to crankcase 30 miles before you change your oil to clean out the sludge. Do a search on seafoam treatment.
Here are some parts suppliers;
read this thread alot of good links;