if you don't know the oil mix, use a safe amount, like 24/1 until you find out.
the correct oil level on most engines is when it overflows out of a bolt hole somewhere near 1/2 way up the case.. sometimes that same hole is also the filler hole.
i dunno squat about dellortos..
nice deal.. $150 for a running bike is very cool.. no idea wtf a Califfo is so can't help you on similar makes.
Hang in here for a couple weeks and search for info on your own. You will become the resident Califfo Expert.