Mark,
Why would you go away from your original working pattern. Laying down a traffic lane spray and then rinsing through is considered standard procedure by a lot of people. Using a high Ph traffic lane (10 or so)and then adding Formula 90 Ph 9.5-10.5 wouldn't be the way to go. Think about the results of high alkalinity from this in a wool carpet. If unsure, check with people like the N.C.C.A.
Regards
Gary