I think you'll be fine for the winter although if the engine consumes any oil you could top up with straight Delvac 0W-40.
Adding as little as 250mls will bump you into the light 0w30 category.
Next OCI (for summer use) if you want to play it more conservatively go for 2 litres of Delvac for a 60/40 blend.
That will give you a 0w30 with a 3.1cP HTHSV and 203 VI.
Still lighter on start-up than a 5W-20 at room temperature and over 20% lighter at OC.
Adding as little as 250mls will bump you into the light 0w30 category.
Next OCI (for summer use) if you want to play it more conservatively go for 2 litres of Delvac for a 60/40 blend.
That will give you a 0w30 with a 3.1cP HTHSV and 203 VI.
Still lighter on start-up than a 5W-20 at room temperature and over 20% lighter at OC.