Yalay

It's not noted on the diagram, but presumably in the event of a net gain of one club from the LL one of the 7th place clubs in the First Division will have to be placed in the following season's Second Division, and as a knock on, Conference X would have to be reduced to one promotion spot. I also wonder why the EoSFL did not consider the possibility of a net gain of two clubs from the LL.

Well then here's one strategy the league could use to maintain a constant membership. With this the league could always have the tier 6 play-off winner play the 18th place club from the HL even before the SPFL play-offs are concluded, and then go from there in determining the final membership for next season, with tier 6 clubs always having a chance at promotion and HL clubs always having to lose a play-off before being relegated. Scenario 1: No club gained or lost from/to SPFL Winner of tier 6 play-off vs HL18 gets spot in HL, as expected. Scenario 2: Club lost to SPFL Tier 6 play-off champion vs HL18 cancelled, and both clubs get spots in the HL next year. Or if the tie has to be played for timing reasons, then the result is just ignored. Scenario 3: Club gained from SPFL Winner of tier 6 play-off plays HL18, and the winner of that plays HL17. The winner of the second tie gets the last spot in next season's HL.

Sorry, I meant going forward. For example the Lowland League always keeps its membership at 16 by relegating anywhere from 0-2 clubs, depending on whether it gains or loses a club from the SPFL. But because the Highland League is giving its last placed club a play-off spot instead of straight relegation, and presumably that play-off will take place before the SPFL play-off is concluded, then the Highland League can't use the Lowland League technique to keep its size of membership stable. So either the league implements a very creative rule or it just accepts that its membership could change year-to-year, which seems odd for a league that has feeders.

Do we know what happens in the scenario where the Highland League gains/loses a club to the SPFL? Does the league just grow/shrink by 1 club for the next season?