Fitting Silentium Silencers on 1978 900SS

I want to fit Silentium’s on a 78 900SS and asking if anyone has them fitted and if so, what model down pipes fit? The original parts book gives the front and rear pipe part numbers ending in 024 and 029 which I’ve never seen available, either new or used? Any advice re fitting would be appreciated.
This bike will be used for touring and I don’t want Conti’s blasting my eardrums for two weeks, getting old and partly sensible.