It is a Rodkicker 30 or a 20? Usually, these are set up with 2500N gas struts, but there is an "option" for a 5000N version. This would be complete overkill on a 42, and would require some serious tension in the vang to pull it down.
I have a Rodkicker 30 on a 50'
Bavaria, with a 2500N stainless gas strut purchased from SGS Engineering in the UK online for about 100 quid. Identical in every way to the original, except it's stainless. Holds up the boom just fine.