I'll jump into the ranking discussion with some observations I've been thinking about recently.
For me, where I QT is an extremely reliable predictor of where I will finish, give or take a couple of positions. I avoid incidents and run clean laps but my pace is usually matched well with the others in my A (for now!) lobbies such that I don't really have many overtakes without mistakes from others. So from that perspective, I've started putting more energy into QT, to mixed results depending on the week.
(BTW - this is another popular topic here. I think the vast majority of us don't overtake much, but if I'm running quality laps and someone spins ahead of me through no fault of mine, I absolutely deserve that position.)
I had a great run a few weeks ago where I was Qing at ~1000 for Gr.3 and my dr went up like a rocket. Alas, it wasn't sustainable, these last weeks I have been back to my typical average of ~2-3k. Still competitive, but the race results has my dr slipping a bit or treading water.
That's for Gr.3.... I have to admit right now that I am hopeless in Gr.4 to the point I've been avoiding it. I'm Qing at 4-6k in this category. I have no idea how I can be so bad there compared with Gr.3, but I can't find the speed in Gr.4. If anyone has "this one secret trick" for driving gr4, please let me know it! I don't really avoid it for dr reasons, but I'm not well matched in my lobbies and it is just no fun! There are occasional exceptions and I'll know just by where I Q.
All this talk about Q and Dr, but I will say, if I just love a combination, DR be damned, I'll go racing.