Pure Class Thief - Which second melee weapon proficiencies? Are clubs worth it at all?

Hi - am currently running an evil-aligned (apart from Imoen) party in a BGT-Weidu playthrough as a training run for the party I intend as my first run-through BGEE. I'm intending to keep Imoen as a straight thief into BG2 (which you can do with BGT-Weidu) and am wondering about which weapon's proficiencies to select.

Imoen started with:

Short Sword *
Short Bow *

At level 4 (I think) I added:

Single Weapon Fighting * (as most bucklers are not great, and the higher crit chance is nice for backstabs etc.)

I'm wondering already, though, about the next proficiency selection for a pure thief that will go onto BG2. The main choices seem to be: long swords (though not the best to backstab with, due to speed etc.), clubs (nice to have a blunt weapon, even though there are no good ones in BG1. The BG2 ones look interesting, though) or Scimitars (nice +2 one on the top of Durlag's tower in BG1, but in BG2 perhaps best to let someone who is dual-wielding use the cool ones like Belem in the off-hand in BG2?).

In my current BGT game CHARNAME is an evil fighter/mage with proficiencies in two-handed weapons (two-handed swords currently, then 2-handed fighting, then staves) and long bows, I also have Monteron, who intends to take proficiences in long swords, to wield the +2/+1 cold Varscona long sword.

I think long swords or clubs look to the best next proficiency selection, maybe daggers even, but am not sure. Are clubs worth it or a pure-class thief in BG2? Any tips on pure-class thief weapon profiencies would be welcome!