30’ is a reference point for the designer to ‘match’ lines too.... all of my 4 weights cast a full head absolutely fine and none feel ‘over loaded’ (as nonsensical as that term is

)... all modern rods will happily cast a line at least one or two weights either side of that written on the rod...
if they were as niche as you seem to think why would lines with longer heads be so popular... or even relevant how come some of the biggest selling lines be 1.5 - 2 times over weight...
the op isn’t a beginner, and he has said he has a decent cast
so the answer to his question isn’t limit yourself to casting 30’ of the head... the gold has a 46’ head of which all can be aerialised...
but rather aerialise as much as you are comfortable with...
and if he can’t control a 46’ head then it’s casting technique rather than him having found the only 9’4w rod in the market that can’t comfortably aerialise a 46’ head...
nothing wrong at all if he can’t, he doesn’t need to on his river...which again he referenced in his post... but that wasn’t what he asked
I’ll leave it with you... and you can keep treating everyone like a beginner who has just picked up a rod.... that’s just what a beginner needs advice from someone who didn’t even know for years there was such a thing as a double haul
ciao....