If i were to set up a test at a lab, would I be able to get results of my THC level, or just a pass/fail like the at home tests?
Depends on how much money you want to spend. Do you want to spend money on a "go/no-go" assay; or do you want to spend the extra money to have a quantitative analysis performed? The lab only provides the "test menu" for the client to pick and choose from.
Also, I am still curious about if smoking after abstaining can somehow slow the THC killing off process?
Depends on so many factors, including - but limited to - pattern of use, how much was used, metabolic rate, and level of physical activity. And each case is different. Testing yourself periodically will give you the answer.