For easy, but good, shore dives, you're probably looking at the Place of Refuge or maybe off the beach at the King Kam hotel (a bit of a surface swim on that one). If the 10 dives is all you still have by then, I'd recommend sticking to that 'til you get dialed in. Once you're comfortable with those you could start checking out other spots. Shorediving.com and Dick Dresie's "Lets go shore divin" website are good references for shore dives. You might want to start off a boat for your first dive as a bit of a refresher.
As far as boat diving goes, the operators here are pretty good about trying to pick good sites based on availability, water conditions of the day, and what people have done/not done and want to see. Unless your 4 saltwater dives were in Indonesia or Fiji, you'll be favorably impressed by just about any site in Kona.
Have a blast!