Lets try and help to get you up n running.
For your vacuum lines, now you are proper single Turbo you really only need a vac line to the FPR and a 10mm feed to the servo.
For inter-cooler V mount is best, for 2 reasons, 1, each "radiator" gets its own clean flow of air and 2 the pipes going onto the inter-cooler will be shorter which helps turbo lag.
For the water rad you can lay it down at 15 to 20 degrees and it will work OK.
Make sure to fit an undertray with a few 50 mm holes underneath the rad.
Back to tuning, forget water meth unless you want crazy boost as this is just more headaches for you, plus its worth knowing I dont even bother with this on the race car.
As for boost and power, just get the thing running and mapped to 0.9 or 1 bar of boost first, bigger power can come later.
To give you an idea, with the race car with the engine that's in the car, we started at 380bhp then as things got sorted, worked our way to 470bhp