I agree with Siv, 1000N is a pathetically small allowable for 400nb pipe. Just not realistic.
A snubber is not designed to deal with wind loads, they resist shock loads and usually need a sudden movement to lock, something like 250mm/min.
Submit your loads to the vendor with supporting data, particularly wind speed and duration, ask for approval or calculations to prove they are unacceptable.
Autopipe .... ??? !!!!