Placing Stolspeed VGs on a Savannah

For the main wing, place the front tips of the VGs 150mm in front of the main rivet line on the top of the spar.  Spacing is 60mm for the first 15 VGs in from the wingtip, and 90mm spacing for the rest.
The Savannah XL and S models can benefit from VGs on the elevator. The VGs would be placed on the underside of the elevator as far forward as the curvature of the surface allows, spaced at 30mm. This will have the VGs hidden at cruise speed but protrude into the airflow when the elevator rotates upward at landing attitude.

The easiest and tidiest way to remove the slat brackets, is just to cut them off about 12mm from the skin, along the profile of the leading edge.  Then they look like miniature stall fences, and you don't have to fill the holes in the skin.

Here's a particularly good looking and simple solution.

The highest point is 18mm from the skin, and the holes are 3/8 and 1/4" to give a feature look.