When to move 1st Lager To secondary

Just started brewing again after a 4 year break. Anyhow, I have my first lager in fridge fermenting away at 50 degrees for about a week now. OG was 1.042 and FG suspected to be around 1.009. Gravity readings were 1.015 (about 80% fermented by my calculaions) today and still bubbling once every 10-15 seconds. Krausen head still there but looks like it is beginning to fall back into beer.

I was planning a diaceteyl rest but not sure I need it as the beer has no hints of buttery or butterscotch flavor. I am going to move to secondary and lager for 3-4 weeks at about 35-40 degrees. Just not sure when to move to secondary.

My question is when should I move to secondary, now before krausen falls back into beer, or wait until the krausen falls back into beer and ferment is completely done?

Thanks in advance.

I'd rack now and let rest in the secondary for the 3-4 weeks. Others will say rack after fermentation is complete. Shouldn't matter much, really...just one opinion!

My "normal" routine is 2 weeks primary 55F, rack to corney 2 weeks secondary 45F, 2-4 weeks lager 35F (depends on how fast I drink 5 gallons). I have done this for about 4 years now. For the last two washed and reused the yeast. I am on about batch 20 with the washed yeast from end on end brewing (and no I did not count)

Rack to secondary once you're at FG or d-rest is done. Lagers are supposed to be clean and crisp. Why leave it on the yeast any longer than necessary?

I have had lagers primary 3 weeks, and ones that primary 4 days. In my opinion the difference between the two has been night and day. The shorter primary ones have been cleaner, brighter, crisper just all around better.

I also lager longer now too.

Thanks for the suggestions, I am at about 80% fermentation and think I will rack to secondary today to get it off the yucky stuff. I think i will leave at 50 degrees until fermentation is complete, then slowly lower to 35 degrees and lager for 3-4 weeks.