Torque for installing Bombshell crank

Dear All,

I want to install a Bombshell Spinnergy Mini crank (2 piece crank with 24mm axle) but in order to do this I need to know how tight the left crankarm fixing bolt should be. The manufacturer has ignored all my messages for this information and I would like to ask if anyone in the group has the experience with these cranks. If not what it the best way to figure out the proper torque?

As a side note, I bought these cranks directly from the manufacturer because he told me that they are Hollowtech II compatible with a chainline of 42 mm (it replaces a Shimano DXR FC-MX70 crankset). Unfortunately this was not true. Installation required spacers to distance the crank from the bottom bracket (otherwise it would not turn) and the chainline was closer to 48 mm.. I had to place the chainring behind the crank to bring it inwards by 4 mm and allow the belt to turn without skipping. It works now but of course it is ugly and dishonesty is hard to swallow.

Thanks in advance

Dimitris