The eleven-day lag is the structural problem, and your Osage County deal is a clean illustration of why. Most county auctions operate on settlement windows of one to three business days, sometimes same-day for online auctions. A custodian that takes eleven days to wire is not a timing issue, it is a workflow incompatibility.
The assumption doing the most work in your original setup is that a self-directed IRA custodian would behave like a brokerage. They do not. SDIRA custodians are trust companies or state-chartered banks with manual review processes, often routing through multiple approval layers before a wire goes out. That is a compliance and custody structure problem, not a staffing one, and it does not get faster just because you call.
A few things worth confirming directly with any custodian before the next auction cycle. First, ask what their published wire turnaround SLA is for tax lien purchases specifically, in writing. Some custodians who specialize in alternative assets (Equity Trust, Midland, a handful of others) have documented expedited wire processes for auction-style purchases, but confirm the actual number of business days, not the marketing language. Second, ask whether they have a checkbook LLC structure available for your account, since that moves the wire decision to you as manager rather than through their approval queue. That changes the tax and legal structure of the account meaningfully, so a tax professional familiar with self-directed accounts needs to be in that conversation before you set it up.
The economics on a $6,200 certificate at 8 percent over six months are thin enough that one missed window, one redemption before you hit the interest accrual threshold, or one title surprise on a property you end up pursuing erases the return entirely. That does not mean the strategy is wrong for a Roth, but it means the custodian selection is not a secondary decision.
What state are you looking at for the next cycle, and have you confirmed their auction settlement window in writing with the county treasurer's office?