As discussed under 1 Nephi 5:22, the critical text will choose between towards and toward on the basis of the earliest textual sources. In this instance, Oliver Cowdery initially wrote “toward the River Sidon” in 𝓞, then virtually immediately corrected toward to towards by inserting inline the word-final s (there is no change in the level of ink flow). The critical text will therefore accept the form towards in this case. In general, towards is much more frequent in the text than toward.
In a nearby passage, once more Oliver Cowdery initially wrote toward but then immediately corrected it to towards, this time in 𝓟; here 𝓞 is extant and reads towards:
That correction in 𝓟 for verse 42 is like the one here in 𝓞 for verse 39: the word-final s is inserted inline in 𝓟 (although at the end of a line); there is no change in the level of ink flow. Thus we have another virtually immediate correction of toward to towards and further evidence of Oliver’s tendency to write toward in place of towards.
Summary: Maintain the form towards in Alma 43:39, the corrected reading in 𝓞; similarly, towards will be maintained in Alma 43:42.