When I built a Helicom Commuter II many years ago there were some retired designers you could hire to evaluate components and/or design any part including an entire helicopter, I recall it was very reasonable.
Any one on the forum know of of any or even if there are any willing to do this sort of thing any longer.
The fear of law suits likely has made them all gun shy, who could blame them.
Mention this just for kicks, In 1970/71 I paid $12K for the entire Commuter II kit including a new in the crate Lycoming 150 HP engine, today the Safari kit is $85K with no engine.
We've come a long ways haven't we
Ken