You are making it difficult to provide help. What I was looking for was
The aim is to isolate driving the 360 degree "servos" from any other code in order to troubleshoot your problem. The reason that I asked for a schematic (a photo of a hand drawn circuit will do) is that any description often leaves too many questions unanswered, as in this case, such as do the servos and the Mega have a common GND connection ?
I am sorry if these requests seem pedantic, but my experience of the forum over many years has shown that the problem is often not where the OP thinks it is or that there are facts not revealed until more questions are asked
The fact of the matter is that if you can command a proper servo to a desired angle then it should be trivial to apply the same process to a 360 degree "servo" to make it rotate at a given speed in a given direction