The way l see it with 2 SL divisions of 12, there will be 6 teams relegated from the Championship next year
There are 9 teams in Championship 1 plus Coventry
lf Toulouse are coming in thats 7 relegated from the Championship to tier 3,
2 promoted making 15 teams, in tier 3, hows that going to work ? NR Cup etc, lot of games, lot of travelling, lot of expenses, for the clubs least able to afford it

I think they're hoping to do it the way NL3 worked back in the day, say Hemel only play Gateshead, Barrow etc once but Skolars, Oxford etc twice. I doubt there will be a NRC and if there is would just be a knockout for third tier clubs as SL2 clubs won't be in it

It won't be 7 relegated from the Championship as they won't relegate a playoff team to accomodate a team that can't win Championship 1.

SL2 will probably be:

Bottom 2 in SL
8 Championship playoff teams
Toulouse
Winners of a Championship/Championship 1 promotion/relegation playoff series

I'd have thought the playoffs would be something like 9th-12th in Championship (bottom 2 would go down anyway) plus the top one or two teams in Championship 1 but the exact format isn't confirmed