We operated a Yak 52 for a few years in the north of UK. The aeroplane lived outside, so got well frozen on cold winter nights.
We never felt the need for oil pre-heating - it just took a while to warm up after start.
In the USSR, they had an oil-dilution system on the Vendeneyev otherwise the oil would have been almost solid on a Soviet winter morning.
I don't think you'll have a problem in Madrid - just start it, warm it, and go flying!