You want the 1.5a (at most)/100AH at Vabs, so having the 2 hr option whichever comes sooner would be wrong for sure. With Wets you can do the 2 hr if you think going longer will cause water loss.
Also that 1.5 if seen on the controller is not the same as amps to the battery, which could be less if some of those amps showing on the controller are going to load. (which you have to guess at with no battery amps monitor).
Going under the .5/100 does not mean overdoing it. (When amps to battery start to climb back up it does mean that) My 250AH AGM gets down to 0.6 amps at Vabs for its Full if I leave it to do that. ISTR LY sees his AGM's low amps number get higher when he has not gone to a true full for a while. After he gooses it, that full amps number goes back down.