Non-destructive testing issues for containers with a diameter less than 800

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There is currently a small storage tank whose shell is made of seamless steel pipes with a diameter of 273 mm and a thickness of 7 mm; the material used is 20#, the design pressure is 2.5 MPa, and the requirement for welds of category B is RT20%. Question 1: In accordance with the requirements for local radiographic or ultrasonic testing in GB/T 150 10.3.2. For non-low-temperature vessels, the inspection length shall be not less than 20% of the length of each weld joint, and in all cases shall not be less than 250 mm. With a focal length of 500, it can be calculated based on a maximum single exposure length of 214 mm. Using 300 mm film, will this meet the requirements, or is it still necessary to use film with a length of at least 250 mm? Two rolls of 180 mm film should be used. Question 2: According to GB/T 150 103.4, for the final ring welds that seal cylinders and heads with a diameter of no more than 800, when a single-sided butt weld joint without gaskets is used and radiographic or ultrasonic testing is not possible, testing may be omitted; however, gas shielded welding must be used for the root pass. If I use a single-sided welded butt joint with a gusset plate structure, is it also permissible to skip testing? Gas shielded welding specifically refers to TIG welding, but CO2 gas shielded welding is also acceptable.