Sure it would be good starter pattern, but be very careful working with silk around the hook point, sometimes that ol hook will just jump out there and snag it.
Put the roll of silk on a bobbin with a flared tip, much easier to control it.
If you have a good Partridge skin go for it.
I think Rover offered some good sizes, and good grade silk helps, a thought on the silk, you want it to lay flat not twisted, so keep an eye on that.
Rough hands can make tying with silk tough, silk will catch on the littlest of snags and fray.
As to how many flies you can get out of a spool of silk? you will get more flies than you will ever use.
P.S. Dave Hughes has a book called "Wet Flies", that would give you some good tips also.