Tubing for a chiller

[knopflerbruce]

I recently tried my water chiller, but I quickly found out that my CHEAP tubing doesn't like the cold at all Will any of these two do the trick down to... say -35c (not sure it'll be THAT cold, but it's nice to have a little headroom)?

Tygon R-3603 3/8" ID 1/2" OD

or

Tygon R-3400 3/8" ID 1/2" OD

I see there are some 3/4" OD tubing, is it worth going for any of those instead? They're a bit more expensive, but if I have I'll go all the way

[Plan.B]

I have used tygon 3603 down to -20C for extended times with no problems

[knopflerbruce]

Thanks, exactly what I needed to know