The entry for the senior competition has risen to a record 97 this season. The under-15 cup, inaugurated last year, has an entry of 84 schools.
Colin Thomson, Scottish Rugby's head of community relations, says: "The schools cups are flagship competitions in the community rugby programme and it is clear that they inspire children to play the game."
Scottish Rugby has outlined its structure for midi rugby for the new season. At both S1 and S2 level, the four districts - Edinburgh, Glasgow, Caledonia and the Borders - will host festivals before the end of November.
Two teams from each district will then progress to the national finals at Murrayfield on March 26.
At under-15 and under-16 level, each district will have club leagues with teams progressing through play-off leagues in February to semi-finals in mid-March and culminating in the national finals, also at Murrayfield on March 26.