That depends. Gravity is a constant ... but gravity isn't always the same. In RET constants aren't constant. I'm yet to work out if your variables vary.
To that end, the Bishop constant can be like an RET constant. It changes to suit the situation.
Then the constant's value is derived from a formula. What is that formula? Is there any way for anyone to demonstrate the validity of the equation listed in the wiki?
The method of deriving G doesn't change to suit a situation. And I thought flat earthers don't believe in gravity?
If you don't know what it is, don't make an excuse. Just leave it for someone who does know.....if there IS anyone. Perhaps there's a paper out there which explains how this constant came to be.