I have adopted Trekking bars, and so I have use of straight bar levers without the straight bars.
Magura HS33 brakes and a Rohloff grip shifter, all work.

My Drop Bar touring bike uses Pre Aero Levers and Scott Peterson SE cantilevers
Bosses are on a heavier wall tube, as iif the brakes are strong, like in #9 above
the frame tubes will be flexed by the braking force. so arch boosters and/or a bit stiffer tube helps.

add : > neither squeel , Magura is Hydraulic rim brake on V bosses.
self energizing brake is beefy, uses a helix and a coil spring in each side
forward motion of wheel increases braking forces..

Squeel is setup more than hardware.