As long as you are using the Talstar P at the proper dilution rate in the tank, the metering rate would just be dependent on how quickly you are walking during application. Unfortunatley, we do not carry Stihl blowers so we cannot give you an exact answer. However, we can thell you that with our Solo 451 blower, we suggest a metereing rate of 2 (from a range of 1-4) for a normal pace during application. For most applications, you will mix 0.5-1 oz per gallon per 1,000 sq ft.
Unfortunately the state of Connecticut has limited most of the products out there on the market these days that can be shipped into the state without having a license to purchase them. Pest Xpert Home Barrier would be one option of a comparable insecticide spray to Talstar that could be used in CT. An all natural option that works similarly is Essentria IC3 and can cover a wide range of pests and usage areas like the Talstar as well.
Talstar is not labeled for cankerworms. The most widely recommended product to use for cankerworms is Bacillus thuringiensis, or B.t. A product like Monterey B.t. Insecticide may be a better option for you. There is a great article here on the treatment and prevention of cankerworms.