RE: Starsurfer holes on bottom
In the kit with the fin screws and footstraps you will find a short piece
of looped over webbing with 2 short footstrap type scews and washers.
This is so you can attach the loop to the bottom of your Starsurfer (using the 2 screws and washers) and attach a tether line to the bottom of your board.
If you get some 1/8-1/4" line, and put a 2 or 3 oz. round "slide on" net sinker a few inches off the bottom, you can attach the tether line to an anchor and your girls can sail out to the extent of the tether line and back without wrapping the tether line around either the fin or the center fin.
Be sure to use the shorter (25 mm i think) screws that come in the tether attachment as they are about 3 mm shorter than std. footstrap screws and using a screw that's too long could damage or punch out the insert in the bottom of your board.
Using the tether line and a suitable small anchor (I like the little mushroom anchors you can get at Walmart, but be sure to take it out and dig it in a bit or better still dig it in until the whole anchor is buried so no one can kick it and injure their foot) you can let your girls practice sailing, completely on their own, in a safe place without worrying that they will sail off into the sunset and need to be rescued.
You can also use the tether line attachment with a longer rope (again with a few net sinkers to keep the rope near/on the bottom in the area of the board so you can let the girls sail out to the extent of the line, and then pull them back in as you coach them.
Hope this helps,