If your engine is broken in you should be running a pure synthetic oil at 50:1 or higher depending on the oil. I am currently running Belray H1R at 50:1 with no residue. As soon as I finish up the liter of that I bought I'm going to Amsoil Saber at 80:1. As for the DL-50, the general consensus seems to be that it out-performs all of the 50s out there including the DA. I get 7400 rpm with a Vess 23A prop on mine. Here's a great thread to read on oil.

http://www.rcuniverse.com/forum/m_65..._1/key_/tm.htm