Runescape – How to Turn Off News and Achievements of Other Players in Runescape

Initial experimentation shows that the bonuses stack multiplicatively: When cutting ivy, which has a base experience of 332.5 experience per cut, just wearing hat and legs for lumberjack outfit gives 3.3 bonus experience per successful cut (about 101% experience). Wearing just the Sköll boots gives 332.5 bonus experience (200% experience as expected). Wearing all of those gives 339.1 experience (202% experience). The bonus from the boots combines with the bonus from the Seer's headband 2+ the same way (giving 220% experience total).

However, wearing the boots and using a sacred clay tool at the same time gives the same bonus as using either individually for a total of 200% experience. This also happens with the combination of the Hati gloves with sacred clay armor and weapon.

In addition, the boot/glove bonus experience does not stack with the bonus from the bonus experience weekend.

The only way to fight with dual-wielded weapons is by equipping a normal one-hand weapon in the main weapon slot and an "offhand" weapon in the offhand/shield slot. These offhand weapons are separate items from the regular weapons, each corresponding to an existing one-hand weapon. Each offhand weapon can be obtained in the same way as its corresponding regular weapon.

Almost every one-hand weapon has a corresponding offhand weapon. A notable exception is the Abyssal Whip, which apparently had animation issues. One other oddity is that dragon claws, previously two-hand weapons, are now separately obtainable as claw and off-hand claw.

As far as I can tell, the only real difference that comes from the extra weapon is the extra DPS.

Almost all of this information comes from this reddit thread I posted.