I’d go for a 14 team league with the teams playing each other twice then,
The top 6 splitting off and play each other a further twice. A total of 36 games - two less but with more meaningful games should increase attendances.
The other 8 join with the top 2 from SPL2 and start from scratch playing each other twice (total 42 games which would give them extra income) and the top 8 at the end rejoin SPL1 for the next season.
This will give all fans more interesting games, TV their 4 OF games, at least 2 Hibs/Hearts derbies and the chance of some good scraps for the Europa cup place/places. It should also give the teams playing in Europe more time to prepare for their games.
SPL2 would consist of 12 teams playing each other twice before the top two go up and the remaining clubs of SPL2 join with 2 winners of regional leagues to form a league similar to SPL1 bottom sides.