A disciplined quarter uses all three calendars. Weeks one and two: watch, don't bid — build comps from Copart and IAA results in your segment. Week three onward: bid your list at the yards whose fee schedules you have already totaled. Manheim sale weeks matter to private buyers only indirectly: their results set the wholesale comps your local dealers paid, which is exactly the number to know when you negotiate retail.
Ledger rule: never let a sale calendar set your urgency. The same segment returns every week; scarcity in a lane is theater.