I must admit that I have a soft spot for white metal Langes.The L1 in pt is my favourite,for some reasons all the Lange in yellow gold or pink are too classic,they look like for old people(apart from an early Grande Lange with black dial and some Limited editions like a yellow gold Dato,which i think was for the Japanese market).Yes definetely coloured golds don t look as good on Langes as Pt or WG.As for the Zeitwerk definetely WG because of the dial if it was Pt I'd say Pt.Yours,Mo.