It's not easy for me to decode your abbreviations (w/i and b/p) 'cause I flunked abbreviation school.
Shooting from prone's best done with a sling from the fore end tip around the top of your off-hand (opposite from trigger hand) arm to the bicep muscle on the same arm. Plant your elbows about 30 to 45 degrees down from where their hands hold the rifle. Adjust the sling to where it's comfortable. Then adjust sling tension as well as elbow position on the ground as well as your body angle to the target and how far apart your legs are spread.
Then test it by first hyperventilating; take 3 deep breaths then let out half of the last one. Hold your breath while aiming the rifle watching the scope's reticule bounce around an aiming point. After 15 seconds of holding your breath, exhale then hyperventilate again. Start over. Your eye's vision starts to get less clear after about 20 seconds of not replenishing the oxygen in the blood feeding it's retina sensor cells.
At some position, you'll see the scope's reticule bouncing around the least on the target. Use those settings every time. Practise getting out of then going back into that position so you'll remember it and do it right every time.
I prefer to use two bags under my front hand on the fore end and one under the toe of the stock helps. I can hold about 1/10th MOA doing this. Tried bipods and never got one to work as well as shot bags full of rice.