I worked out that if its two up two down with teams folding taking out relegation, with teams from lower divisions filling those spots meaning more promotions, two down from combo be that holmans and goonhavern or illogan without any further teams folding it would be as follows:
Combo: Relegated; Holmans, Goonhavern or Illogan depending on that outcome.
Prem 14 teams: Promoted; Lizard & Wendron. Relegated; St Keverne
Div 1 14 teams: Promoted; Mousehole Res & Penwith Exiles. Relegated; N/A.
Div 2 14 teams: Promoted; Newlyn Lions, Probus, Goonhavern Res & Wendron 3rds. Relegated; Storm
Div 3 15 teams: Promoted; New Inn Titans, Ruan Minor, West Cornwall Res, Falmouth DC, St Ives Mariners & Ludgvan Res. Relegated; Newlyn Non-Athletico Res & Carharrack Res
Div 4 13-15 teams: Promoted; Praze, Penzance Res, Perranwell, Mousehole 3rds, Wendron 4ths, Troon Res & Lizard(depending on dropping div 3 to 14 aswell) then leaving room for 5-7 teams.
So as close as possible thats what it could be depending on any other outcomes i.e teams folding, 3 down from combo etc