Maybe thats why rifles with torx head screws dont always shoot straight...cos the slots cant be aligned to the direction of the bore...
Flashman, with my synthetic Tikka sporters i started at about 30 & went up...
On my Tikka's 25 felt like it was only just nipped & they proved to loosen easily...
Anything over 40 just feels too heavy for the stock--no science here though...just feeling...tight enough to hold & no flex when tightening between 30 & 40.
Ive ended up with 35 on rear & 40 on the front...
Im probably not much help, & im no expert & dont own a Howa...but atleast thats a number to hopefully get you started.
Maybe if the howa has pillar you could start tighter
.
Im sure some others who know better will chime in at some point.
The man who knows everything, doesnt really know everything...he's just stopped learning...