Assuming you mean offhand for Mandau -- Spreadsheet says Aluh should win by betweeen 0.5% and 1.0% if attack is capped (depending on varying factors, and assuming the extra 1 str on the Thokcha doesn't raise fStr), and be near identical if attack is not capped.
If you gain an fStr with Thokcha, Thokcha wins by about 1.5% in non-capped attack situation, 1.0% in attack capped.
Overall, you'd be hard-pressed to find any meaningful difference between the two.
I hate questions like this, because there are a ton of other factors that come into play when asking them. But Motenten reads it, and plugs a bunch of things into one of the stellar spreadsheets, along with a bunch of other gear, and comes up with that answer. I am sure it's either exactly correct or very nearly, and if he'd been asking it, I'm sure he could be satisfied.
But the answer already shows what's ridiculous about it -
if attack is capped -
assuming fStr isn't capped -
if you gain 1 fStr. All of those things would be known to Motenten's THF, of course, because he'd also know what other gear was on, what buffs, what merits, what mobs. But what does it do for OP? "This or that, what's better?" Not too much.
I think Motenten should just reply to every question with a link. :)