What is a good way to check and align twin bravo drives with hdy inco steering

Measure center-to-center on the prop shafts and center-to-center of the bullet on the back of the drive. Then adjust for desired toe-in/toe-out.

What the toe in or toe do to the handling of the boat my drive spin outwards

Toe = Nose cones of leading edge of drive/s.

There's been a couple of posts on different boards relating to the same topic. Many, many different opinions, as usual depending on make model yada-yada. As a "rule of thumb" if drives spin out no more than1/8" toe out (drive cones out further than the propless propshaft measurements).

If props spin inward, toe in no more than an 1/8" (tips of propless shafts out further than the center of cones). Various reasons, but that's the gist.

Start with dead even (cones/shafts exactly the same distance apart) note performance/handling, then work out/in depending on props rotation in 1/16" increments, or if feels great even leave it alone.

Thanks for the help by the way what would be a noticeable change?