Try to cover it at idle just for fun and to see the difference. The differnce at higher loads and revs will be smaller.
You can´t cover it at higher loads. It will burn in seconds.
If you position it where all three outlets meet, you will just get an average. And in your case it won´t work anyway.
Best would be to get all three cylinders individually.
But to get some good basics you can start with one cylinder and will already get pretty close.
As the front cylinder has the longest line you should start with that one.