lager temps?

Doing my first pils. 10 gallon batch split into 2 buckets. After pitching I left it at room temp (70 degrees) for a day then droped it down to 50 where it stayed for 2 weeks. I transfered it yesterday to the glass and found 2 seperate readings; 1030 for the pils lager, and 1020 for the czech pils. Its still at 50. Do I drop it to the 35-40 mark when its done fermenting, or right before? Whats the scienc/art behind the temp drops?

I don't have the grain bill on hand.

Found this here- http://www.brewplus.com/forum/alt-beer-home-brewing/1597-lager-temps.html
"My experience with lagers is DON'T pitch until you get the wort to
fermentation temps. Every lager I've pitched cold has been better than
any lager I've pitched warm. Make a LARGE starter...it's not uncommon
for me to make a 2 gal. starter for a lager. Aerate REALLY well.
Ferment at 45-55 for 2-3 weeks, or until you're witin a point or 2 of
your FG. DSon't worry about how long ot takes or be in a rush to get to
secondary. After primary is nearly done, you can raise the temp to the
mid 60s for a couple days to do a diacetyl rest if needed. I usually go
to secondary at arounf 45F for a couple weeks after that, but you can go
staright to lagering. Lager at around 35F for at least 2 months, or as
long as you can stand it!"

I pitch cold - 44F and slowlywarm it up to about 52F over 48-72 hours. This avoids the need for a diacetyl rest. Some pitch warm but I'd guess that 70 is too high. Dropping from that to 50 in a short period of time likely triggers floculation and the yeast shut down which would explain your high SG currently. I would not cool it further at this point but let it go fo a few more weeks at 50 and recheck the SG. Alternatively pitch some more, active yeast.

GT

Agree, pitching cold yeast into fermentation temperture wort is the way to go.

What PJ and GT said goes.