I have a modern B=BB Woolf. I have a '50-60's 146 OB that is narrower.
My 243 1/2 KOB is also a true old style OB, like a modern fat M....which is a writing nib, not a modern signature nib.
I have other wide nibbed vintage pens, like Osmia OB which is like a modern fat M. Or the OBB's that one can write well with.
My Pelikan 500 is a very wet OBB...could if I start using it, try to press the tines together to make it dryer. That is indeed a signature pen.
Many/most vintage nibs are narrower than modern.
To make a nib 'wetter', with thumb nails at the shoulder spread the tines a tiny bit. I would not put the blame on the feed, nor would I butcher it trying to fix what appears to be a nib slit width problem.
Your nib looks wide enough to be at least BB...could be BBB as described....but remember there is always a narrow and wide part of size in tolerance. It is possible that a fat F can equal a skinny M...exactly. Here it could be a skinny BBB=a fat BB.
Ron Zorn has a great article in the pinned Sheaffer sub section here, showing that in the Fort Jane factory nib gauge tolerances. Then there are those that are a hair deeper into the tolerance; that you can not tell by eye that it has backed towards the center of the tolerance range. Still looks a bit fat for a F...or thin for a B.
Should I ever order a replacement nib again on a pen from any company...I will tell them I want it in the middle of the tolerance, not on the fat size like that modern B=BB nor would I want one on the skinny side where a B would = a fat M.
When one sends in for a replacement, they should have enough time to find one that is in the middle of the tolerance range.
Today many want a fat signature B....instead of a writing B of vintage era.
Do try one of the wetter Noodler inks....that could make the nib write as fat as you wish.