Don't think it's quite worth that; We wouldn't get the border expansion until after t100. If we get the granary, grow straight to size 6, we can get a settler out of that city for the horses prior to that. If we chopped the lib growth would be slower to the extent we probably couldn't get a settler out without not growing after we get representation. The forge would also be alot further behind; we do need that for happiness. Now, City 5, at size 10, can make 30 beakers without a lib, or 37.5 with (with a little food deficit, so the value changes slightly as resources come online), but we don't need the lib until it hits size 10 at the latest. Now, we are going to come close to crashing our economy; we can't rely on the slider to make beakers, we have to make them with specialists (if we lose pyramids, then we need to drastically redesign the plan, I already have a few ideas but they aren't great so far, and need improvement). So we need that city 1 food off growing into unhappiness, and can't really wait around much because that screws up our teching ability.
So, if the aim is to get horses asap, then 1 or 3 makes sense, but we don't need them asap; a better aim would be to have horses available by turn t102 (it is a fair end point, we would have reached a stage where letting our economy get going without adding more cities would be prudent, and would let us get a few extra units for front cities as well as scouts). Getting a lib there asap to pop the borders would lead to the borders popping a little afterwards, so is...acceptable, but planting a city for them would be better from a growth perspecitive if we see any food for a horses city, so we need to scout out that land to see if it is viable.
Possibility for Barentz, maybe?