Jett's Free Mastery Book Question

i got myself rapid fire
I think i should have went with eatons (suborbital bombardment) since that seems to be like a main leveling attack 120-130s

You can probably do the neo city chain from Andy to get a free suborbital bombardment 30 book before you're actually stuck needing the skill points. I thought that taking the AoE skill would be a good call, too, but I also took rapid fire because I had no idea what Eight-Legs Easton was or if it was even a Jett book.