Bolts for the water pump thermostat housing

[YoRHaOperator]

Relatively new to the forum, as well as working in cars as a whole, I was wondering if anyone had the sizes for the three bolts that hold the water pump and thermostat housing? Alternatively, any tips for how to find the sizes without just guessing at random?

 

[AndyB.]

Try 6mm x 70mm.