ok, i've thinned out the boards to 5/8", and spaced them to a 3/8" gap. i'm not too fond of it for the following reasons, it triples the number of mortises and tenons needed from on pair to three, unless the holes for the dowels (and i figure 4 holes) are drilled all the way through, resulting in the end grain interrupting the flow of the grain, locating them will be difficult enough, instead of 3 holes to round out at the spindle sander, there are now 9, increasing the opportunity for error, and with widening the fin like this, overpowers the base, and would result in needing a proportionally larger base, and that is not an option, as this is intended to be a bar/counter top holder. i am posting the 3 versions of the holder, the first, the second which i like, and the third with the spaces. the third version only increases the contact area by a touch over a half inch. i checked something, if i held the bottle in one hand, with only the first 3 fingers, and thumb holding the bottle (sorry pinky!), the three fingers together measure up to a touch over 2", and i think that's enough to hold the bottle in place, with a close fitting hole. the key to this design working is the close fit of the holes for the bottles.