Railgun Manga

I've now read the 8th volume of the railgun manga, really enjoyed it and cant watt to read volume 9 which I will be ordering on Wednesday, I'm still not sure whether to start the light novels or index manga first guess I'll need to make a decision soon as the next 3 volumes of railgun manga aren't going to hold me down for every long =D if anyone has a suggestion to which I should read first (Index Novels or Index Manga) please let me know either leave a comment here or leave a message on my message wall.