I haven't broken 300 yet on PGL, but both crafts I did today I had a 500+ SP gain. As PGL though I wasn't ever seing major SP gains any way with normal srikes so I dunno if it's hit based still or what the new formula is.
The 300ish I was getting was on enemies netting 300ish xp and the 100ish SP gains were also on high 200 XP mobs all with GF activated so I don't think the SP is based on XP. I wonder if the formula is like the old one, but only with a guaranteed amount of SP per mob... I really don't know.
Maybe if we all ask and use words like malarky they'll put it in the next ask the devs... now wheres my thesaurus.
FFXI:Sylph - Perrin 75 Hume THF; Retired (At least from my use any way)
EVE Online:ScraperX; Retired
WAR:IronClaw- Peryn SW;SkullThrone- Grymloc BO; Retired