My problem is the fact gunbot seems to ignore BB at all.
I don't defend GB as it has a lot of problems and things to be fixed...
BUT your very first problem here is that you don't know GB's BBs, which are different from Bittrex or Polo's ones.
In short trying to think how it works using your market place tool is a no-go, very sorry.
So many posts in forum about this... please search.
Start slow. One stable or climbing pair.
GB is NOT a fast earn system, it's for sure a LONG learning curve, with *maybe* a profit somewhere, later.
Please also understand you can (and should) be happy of a 1% profit made, but if Bitcoin loose 10% (vs fiat) like today... then you've to be ULTRA patient.
Good luck.