It was top four when there were nine teams in 2011 and 2012.

You would only go top 5 if the #1 team got a week off.

Week 1: 1: bye, 2 v 3 Qualifying; 4 v 5 Elimination
Week 2: 1 v Winner 2/3, Loser 2/3 v Winner 4/5, Loser 4/5 out
etc etc

You would only go top 5 if the #1 team got a week off.

Week 1: 1: bye, 2 v 3 Qualifying; 4 v 5 Elimination
Week 2: 1 v Winner 2/3, Loser 2/3 v Winner 4/5, Loser 4/5 out
etc etc

That SANFL model looks OK.
Week 1 both one off games.
Week 2 both best of 3
Grand final best of 5.

Why does the format need to change with 9 teams?

With 4 of the top 8 currently in the finals, 50% of the field has a chance. Add another team and make it top 6, 66+% of the field are in the finals. Why? Let's talk again when we get to 10 teams...

There were a couple of disgraceful years where the NBL was top 8 out of an 11 team comp or something. There is a very small asterisk against the Wildcats' 31 year finals streak as they benefitted from this in one of the years coming, if I recall correctly, 6th or 7th out of 11 teams, with a losing record.

"Because 4/9 means less than 45% of the teams make it... Generally around 50% feels about right."

You're trolling, right?

Ok lets be honest here, an extra team still using the 2+2 home and away season games vs each team means we may eat into where the playoffs are maybe a week or 2 later so why fiddle with the 3 game series semis and 5 game grand final series.

Give us more games during regular season but keep playoffs as is... just play them on better days (Friday and Sunday instead of Thursday and Saturday) like we have had in the past.

Week 1 4 v 5 Best of 3 (1,2,3 bye)
Week 2 Semi Finals 1 v 4/5, 2 v 3 Best of 3
Grand Final Winner Semi Finals Best of 5

Same as above but with 4 v 5 being a one off game.

Personally, I don't fancy the notion of a team that wasn't good enough to win at least half of its regular season games making playoffs. I reckon the 6th placed of 9 teams would have a losing record more than 80% of seasons. I also think 5th placed team would have a losing record in about a quarter of seasons.

Here's NBL number of teams and Win-loss record of sixth placed team for each season since 2001:

2000-01 11 16-12
2001-02 11 16-14
2002-03 11 15-15
2003-04 12 16-17
2004-05 11 17-15
2005-06 11 17-15
2006-07 12 17-16
2007-08 13 16-14
2008-09 10 15-15
2009-10 8 11-17
2010-11 9 13-15
2011-12 9 11-17
2012-13 8 11-17
2013-14 8 12-16
2014-15 8 11-17
2015-16 8 12-16
2016-17 8 13-15
2017-18 8 11-17

Shows that the 6th placed team has needed at least 5 more teams below it to achieve a winning record. It needed at least 4 below it to break even. Less than that and it had a losing record.

4 v 5 shouldn't be a one off game. It makes a mockery of it. Plus 1 game won't hurt them physically. Needs to be 3 games so it's a test of the mind, body, and spirit and gives an advantage to those who finished higher.

IMO, increasing it to a top 5 is largely pointless unless the 5th placed team gets a home game out of it, therefore I wouldn't bother doing a one-off 4-vs-5 game. Who benefits from that?
(Personally I'd keep it a top 4 until there are 10 teams anyway)

Well at least with "9-team finals" the Wildcats streak would be safe for a while

But seriously, I would stick with 4, until we had at least 10 teams.
Especially when some of our teams continue to suck balls

Shouldn't change. It's one extra team. We live in a bit of a "everyone gets a prize" era where you have to be seen to be exceedingly fair. But no, we shouldn't need to come up with mathematical magic to shoehorn more teams into finals when we have a league of 9.

There's also the fact that the playoffs come and go so quickly, and more playoff games would be a good thing. Expanding the league is the way to get there though, and I think you need at least 11 teams before moving to a top six.