TL/DR
Keep division leveling simple. If a person misses, they stay put, but the divisions are leveled without the expectation that they will be there next week.
Leveling should be based on lap and gap times, not based on podium finishes.
There should be rewards for D2 and D3. They should not be viewed as punishment divisions.
Leveling should be based on what would create close racing. Winning or losing in a division doesn't tie directly to promotion or relegation.
Perhaps the divisions should run different car/track combos, or perhaps car/track selection shouldn't be done solely by D1.
The Full Post
Looking back over the responses, I say just keep it simple.
I say keep them in the same division, but put them in reserves. We've been balancing the divisions so there are about 9 to 11 drivers. So, really, we have enough room. If they don't show up, they just stay, and we balance the divisions as though they aren't going to show up again. They stay put.
And if we ever get enough people in a division that we fill the room, then we give priority to those that were here the previous week.
We had 19 eligible for D3 this past week. The most we had for any one race was 9. We only had 7 finish all six races.
There is something else I'm thinking though...
I don't look at D2 and D1 as being the goal. The reward for doing well in D3 shouldn't be you get promoted. The reward for doing well in D2 shouldn't be you get promoted. I look at promotion the result of trying to put people together that run the same speeds, so the racing is tighter.
As a result, we really need to introduce rewards for the winners of D2 and D3, and we should only be moving people between divisions if their times would make them competitive in that division.
Like I said, we had 9 people at most in D3 this week. Only 3 of us truly should be D3. Maybe, just maybe, you could say 4. Why not just look at the results, focusing on the lap times,and put people where they belong.
And then, at the end of a Sunday, Bob Binklow wins first place in D2. He gets an award, a parade, whatever. Woot! Good job, Bob! Yeahhhh!
Does he get to go to D1? Well... that depends. If his times are faster than someone already in D1, then yes, we should shuffle those people. Are his times way faster than the rest of D2? Did he dominate, or just simply win a close race? But if not... if he isn't much faster, well... then he stays in D2.
Make sense?
I know it turns the whole thing on its head. But... I think maybe we are just looking at it wrong. We are looking at it as though being in D2 or D3 is a bad thing. It is a punishment. It shouldn't be. Being in D2 or D3 simply means you are grouped with other like drivers so you can actually have a close race.
So, another thought...
Which makes this post entirely too long and I'm sure no one will actually read it.
Why not have the divisions slightly different? In the real world, drivers see F1 as the pinnacle. Yes, you may be good, but you aren't great until someone is willing to spend the money on you to put you in a very fast F1 car. So, until then, you are put into slower cars. IRL, F3, F2000, Kart. It may create confusion, I can understand that, but... I still don't see why each division has to run the same cars?
At the very least, D2 and D3 should have some input. D2 and D3 shouldn't be punishments. We shouldnt' be considered as inferior and less worthy. We shouldn't have to bow and grovel as D1 sets the car track combos.
Yes, blasting around on some leery, over-powered car might be fun for the uber elites, it might promote close racing in D1 (I don't know, I haven't see the times posted to the spreadsheet, yet), but it spreads the field in D3.
I think the Viper, on an appropriate course, could promote close racing. I think SSR 5 is just not it. Particularly since there is no need to practice it since we don't know how long it will stick around. Mind you, some of us can't practice it because we are casual, and Sunday may be the only time we get to race.
That 'Vette, though... perhaps on an Oval? Other than that, I'm not sure if there is a place where it is going to promote close racing.
And I can understand that D1 wants a challenge, but... there are three divisions, and again, D2 and D3 shouldn't be viewed as punishments.
One idea is using the three first place finishers.
Another idea is rotating selection. This week it is the podium from D1. Next week, the podium from D2. Next week, the podium from D3, and so on. (And it should rotate down, to keep someone from following the rotation and being on the podium for three weeks in a row and having selection chances three weeks in a row).
Sorry, this post is entirely too long.