The thing with wide longbows (like warbows) with width around 40 mm is that they (to certain point) have less deflection if you also lower the brace height - because the aditionall push will flex the arrow more. And that must be tried.
Jaro
With any bow you get more deflection from the aimed line as the string returns to a lower brace height.
The fact that the shaft will flex more because it travels slightly faster with a longer power stroke and the increase in offset due to the lower brace will tend towards offsetting each other.
All that remains is to match the shaft to the bow as it is used.
Or not, as you please....
Try fistmele as a starting point and adjust from there if necessary.
I shoot instinctive unmarked field with a single stave yew of the old type, but I run a higher than normal brace height and draw short (bowhunter corner of the mouth at 29" because I am more accurate when I do so for this purpose and the speed is adequate to the task in hand.
In other words I optimise this bow set up primarily for lateral accuracy at close to mid distances rather than for cast.
You make the compromise that bests suits the intended function.
If you are concerned with cast and distance, find the lowest brace height that you can manage cleanly and shoot straight.
Then look to your extension and loose.
If your drawing side wrist is bent at "full" draw, like it or not, you are under drawing the bow.
If you do not make a straight line from the drawing side elbow to the mark and extend into the loose you are giving up cast.
This is true of any draw weight, be it 5 lb or 150 lb.
Rod.