| Not sure I'm interpreting this correctly, but a reason I've noticed in my area that has made me want to avoid loose gravel (unless in can be compacted) or small stones is that leaves get caught in the stones and it's almost impossible to keep the area looking "cared for". I may not understand what you mean by gravel, but in this man's opinion areas of relatively "loose" stones work best in areas where there is little or not leaf fall. In the South where we have lots of warm weather and rain, if I didn't put down a 5 or 6 sheet layer of newspaper before I put down the fabric something would have sufficient life left to pop through. Personally I don't see the purpose of sand under gravel unless it will save you money by making the gravel layer thinner. Let us know. I really haven't a clue about how effective this would be. David | 
