External Perimeter Resonance Issues - stretching/scratching marks on outer shell

I'm trying to figure out my best quality & speed settings for external perimeters to make the outer shell of the print. I've tuned extrusion, flow rate, temperature, cooling, etc. and am getting very good results as far as the tops and bottoms of things go, so now I'm onto Resonance, Pressure Advance, etc. I'm following the https://www.klipper3d.org/Resonance_Compensation.html guide, so Input Shaper and PA are off. Attached is my latest tuning tower, and a recent best surface finish print Settings: Enclosed V-Core3.1 - 500 | 48V 5160s, Carbon Fiber Gantry, latest toolboard & beacon This tuning tower is running from 500 mm/s2 to 6500 mm/s2 accel External Perimeter: 100mm/s Normal Perimeters: 500mm/s Max Flow Rate: 24 mm3/s throttles back the high perimeter speed most of the time. ASA 250/110C fan at 40% I typically print with external perimeter speed at 3k accel and 180mm/s but that and anything higher on this tuning tower is horribly ugly with these stretch marks/striated gaps. I understand this test is usually about ringing and resonance frequencies, but that's not my main concern right now. My questions: 1. Is there a term or name for this other diagonal distortion/scratching texture I'm seeing at higher accelerations? 2. How am I supposed to address this? Do I just have to accept this test at face value and print external perimeters at 100mm/s at 500mm/s2 accel (the bottom of the tuning tower) or even slower? 3. Is there some critical setting/parameter I could be overlooking? For how clean & fast I've been able to get the infill & top surfacing these numbers seem unusually slow to produce a very high quality & visually consistent outer shell, but my perspective is limited.