I have used Anchor Buddy for many years to great satisfaction.
The modification you mention that doesn’t make sense to me is the additional non-stretch line between Anchor Buddy and the dinghy. While it will allow the anchor to be placed further from shore, I don’t think it will keep the dinghy further from shore. Assuming you take the dinghy all the way in to disembark, the distance the dinghy will be off the beach will be limited to the stretch range of the Anchor Buddy.
Also, I have found that a 5 lbs mushroom anchor is adequate, but I have a lighter dinghy
We use our anchor buddy and appreciate its design as well! One thing we struggle with is the extra shore line getting tangled up, so will definitely consider the electric cord reel you suggest! We use a folding claw anchor which is very easy to store, and that has held well for us so far.