important or just wack it anywhere, any angle
of take off pipe, any lenght? !!!

 

the better the flow to it the better a certain size wastegate can control boost.
good to have a smooth takeoff in the direction of the gasflow, ie a Y piece, one going to turbo, one to wastegate.

that doesnt mean its vital, look at even turbo F1 cars etc and you can see their positionings wasnt as ideal with right angles and odd positions for it, but they had big wastegates and big boost, so no need to be so careful.

in my eyes as short a pipe as poss to the gate too as until its open a blocked pipe will cause gas reversal, but again, seen lots of very serious race cars with long pipes to the gate, mainly to make them fit.