Well, here's my mindset. Arnie seems to be tricky to nail with a bust. I've been a big fan of his for many years. This bust is from a laser-scan done by Gentle Giant for T3. This bust (to me and with sunglasses on) looks to be the most accurate one around. If you look closely in person, you can see indentations of his pores on the bust. That's pretty incredible.
Your other options just will not have the same level of detail as this one. You can get the sideshow one, but it's not really 1:1 and looks too thin. You can turn this one into a T2 version by getting rid of wrinkles and basically losing detail.
My family (who are not into this stuff) couldn't believe this bust in person. They just kept staring at it. Normally, they're like "ok, what did you get now...........how nice."
They were kind of freaked out at how real it looks.
Just my point of view. I'm very happy with it. Everyone thinks Arnold looks cool in T1 and T2. I think he looks cool in T3 as well. Yes, he has aged between T2 and T3, but to me it's no big deal.
And I guess if all else fails, you could just change the sunglasses to the T2 version.
I hope I helped out with some insights.