...factor in the reduction of At Bats home favourites have when winning at the end of 8th.

Road dogs on the run line provide some value here as

1)if home fav is winning after 8th inning, road team get full At Bats regardless if they are in the lead or not, home favs behind end the game if they get at least one run ahead in game.

2)road team always get to complete 9 innings worth of At Bats

You are absolutely right about this.

That's why I would prefer to take the Yankees as a Road Favorite instead of a Home Favorite.

GL.

adds more value to the sf and nyy plays

Yep.

I've had more luck betting on Offensively dominating teams as RF's on the RL.