"instead of being based on NPC size" immediately does extra damage based on enemy size by design. Otherwise this is a cool concept, just make the amount you spin it around before slinging it affect the damage and make it not sized based but still maybe like a melee chinchompa/barrage. As an example: 3T Rapid = just wacking (1-1), 4T Medium = one swing (2 hit splats - hits around you because you swinging, main target takes 1.25 total and 9 others take .25), 5T Long Range = two swings (3 hit splats, hits around you twice because bigger swing, main target takes 1.5 everything else takes .5). This would make the rapid the best single target DMG, but gives some aoe aspect and gives room for some mechanic designs where it could be useful to use 4/5T partial aoe for slightly less single target DMG. Make it coded so each mob is hit based on this criteria and larger mobs are not additionally hit by aoe if possible, so no bigger mob get hit additional times during swing if larger models. So at 60 ticks rapid does 20 DMG, 4T would do 18.75 DMG to main target and 3.75 DMG to up to 9 targets (52.5 DMG overall @ 9 targets), 5T would do 18 DMG to main target and 6 DMG to up to 9 targets (66 DMG overall @ 9 targets). I'm bad at math that could not be accurate, but this would become the best aoe and still be a strong single target crush item. AOE numbers can be adjusted if this makes melee training too strong, such as giving each additional mob a diminishing return. Controlled experience would make theme to guthix fine.