IMO the larger chance of winning(-7) outweighs the smaller % of profit with the -7.5. Too many times I’ve lost a wager by a point

-7.5 at -105 is the better maths then -7 -110, but this question is base on score. TD =7, But having a -7 at -105 and -7.5 at -110 is a fishy line. meaning if the books don't care about the extra .5 that much, i would be paranoid about the bet in the first place. And there go's Snap making another bollox of a question, Sorry
Books are given you 5% less cash on -7.5, But given you around 7% extra on the score.
or
7% less on the score for 5% extra cash on the -7

we are not laying 7.5 -105...7 is a key number in MLB and that half run is worth more than the 5 cents...Lay the 7 -110....Typically a half run is worth 20/30 cents...I would say on the 7 that the half run is worth 30/35 cents..So it makes no sense to lay the 7.5 -105. You are actually losing value betting the 7.5.

Depends on the sport
But -7 (-110) is better
One reason is is you were to buy 0.5 it would cost you more than 5 cents juice
In football it will cost even more to get -7
So that’s really a better play