I think that plan completely deviates from the solicited advice. As stated, start .020 off of the lands and work back in .005 increments. Using a bigger gap could very possibly miss your accuracy node altogether. Load development at 300 yards is also bringing other factors into the equation that could cause a misdiagnosis of the accuracy node. Just my 2c. Check out Eric Cortina on YouTube, he offers excellent advice on this subject and he shoots berger bullets almost exclusively.