Whats better for high alchemy?

Should I high alch small items with small profit such as addy full helms (49gp profit) or big items with bigger profit such as rune pskirt h5 (349gp profit)....you may be thinking, "duh, the rune plateskirt h5!" but if i use tht i cant buy in too much bulk like the addy helm. So which would yield more xp and be all around better? Thnx! F2P ONLY...