Power steering fluid: semi-synth or full-synth?

Dear forum members,

I need to replace the power steering fluid and the workshop manual gives 2 choices, of which I will go for the Cold Climate PAS Fluid 14315 LRN2261.

I have 2 choices of this oil - full-synth and semi-synth. What would You advise, is going full-synth safe for the gaskets and seals in the power steering system? Should I go for full-synth?

THANK YOU!!

Ok, guys, sorry for false alarm.. Found this sentence on the Texaco (suggested by manual) liquid spec: Cold Climate Power Steering Fluid is a high performance semi-synthetic power steering fluid.

Semi-synth it will remain

Do you live in a cold climate?

I live in Estonia. Not that bad, but we have a regular -20 and down to -30 degree celcius every winter for a week or two. I could use any help I can get with making oils more viscous in those weathers. We have summers of +20+25 with rare occasion of +30*C. Do You think that makes it more reasonable to go the other type of fluid called ATF Dexron IID or IIID?

It depends, can you get hold of the spec? I think I would spec the oil for cold weather if it were me, the reason being the system could probably handle thin oil better than thick oil.

Is this what You mean?

https://cglapps.chevron.com/msdspds/PDSDetailPage.aspx?docDataId=327153&docFormat=PDF