The B&G SpotSprayR Sprayer (#24000107) is 16 oz.
Yes, the top of the B&G SpotSprayR Sprayer (#24000107) is plastic.
According to the manufacturer, the tops of the B&G SpotSprayR Sprayer (#24000107) and the B&G QT-1 Handheld Sprayer with Adjustable Tip (#17017401) are the same.
The B&G 4 in. Wood Injection Tip (22071827) can be used with B&G pump sprayers only but requires Tip Cap Part 1325 (sold separately). It would not work with the B&G SpotSprayR Sprayer (#24000107). The B&G 1" Wood Injection Tip Whit-1 (22071824) could be used but only with the B&G AccuSpray with Termite Injection Tip as a replacment.
The B&G SpotR Sprayer comes with an adjustable nozzle that can range from a pin to a cone spray pattern. The pin stream would be used for crack and crevice applications. If you need a more narrow stream or tip, you would have to use a different device as there is not a C&C tip available with a straw on this unit. You may find an aerosol application will work better for you in this scenario and use the crack and crevice straws for direct void treatments.
We are not aware of any extension tips for the B&G SpotSprayR Sprayer (#24000107). We recommend contacting B&G and asking if the wood hardener can be successfully used in this type of unit as we are not familiar with the chemical. (800) 544-8811
B&G SpotSprayR Sprayer (#24000107) has 30 psi. This is a metal bottle with brass tip.