I only use the twizzle stick once, immediately after my first agitation cycle of the entire developing time. I spin the film both directions once in hopes of dislodging any air bubbles that might continue to cling to the perforations after I tapped it on the counter.
After that, I leave it alone...
I use Patterson tanks with plastic reels for tank processing.
My agitation method is to put one hand under the tank, one on top and invert it while twisting and then twist it the opposite direction upon returning to upright. I then grab the top of the tank and rotate it in about a foot wide circle (like you are stiring a large pot of soup), snapping to a halt and firmly bringing it down on the bench with a tap.
I cannot remember having surge marks in the last 2 decades.
After that, I leave it alone...
I use Patterson tanks with plastic reels for tank processing.
My agitation method is to put one hand under the tank, one on top and invert it while twisting and then twist it the opposite direction upon returning to upright. I then grab the top of the tank and rotate it in about a foot wide circle (like you are stiring a large pot of soup), snapping to a halt and firmly bringing it down on the bench with a tap.
I cannot remember having surge marks in the last 2 decades.