I for one like the theories that Russ Landry put out the beginning of this year (view article here) in regards to calcium movement in the pumpkin plant, blossom end splits and low fruit weight. I saw the impact last year that a lack of water and the inability of the plant to absorb calcium can cause on the fruit. If you are interested take the time to read the article.
To help build the pathways for calcium and nutrient movement within the pumpkin I have been giving the plant a fair amount of calcium these last three weeks. I don't know how much is to much but I don't want to be to low like last year. This evening I gave the pumpkin plants a touch of Nutri-Cal, calcium chloride, CalCarb, humic acid and seaweed. The seaweed was thrown into the mix because I read a study this week done on grape vines that found that giving the plants some potassium right after giving it calcium caused a significant increase in the absorption of calcium. The Auxins in seaweed also has an effect on cell elongation which can improve growth.