30 days is fairly standard for an initial SI issuance as a minimum provided everything is provided exactly as demanded. Renewals are usually not problematic. I let my SI lapse and did a "redo" this year.
Submitted all reports and took medical on the 13th. SI authorization was issued on the 26th. I did not use any medical service (ALPA, AMAS, etc). I thought it was fairly efficient as I was expecting it to take much longer.