Spidertrax are the most common spacer run so I'd go with those.

The biggest thing about the spacer is getting the tire sidewall away from the balljoint bolt. But the larger the spacer, the more likely you'll have rubbing issues in the pinch weld area while turning.

1.5" spacers are common because they don't require cutting the wheel studs. But with with JK wheels i believe there's indents on the back side of the wheel that clear the stock wheel studs when used with 1.25" spacers (might want to double check that). So the 1.25" spacers will clear the bolt and minimize rubbing at the pinch weld, especially the passenger side if you have the rear HVAC lines.

255 vs 265 is the tire width in mm. 255 is 10mm thinner than 265, which is ~.5".