If you're undecided, here are a few data points you may want to consider
Hell, most Pauper decks I see tend to barely even run twenty
Cards like Manamorphose are especially good with recursion effects
It can be blinked by Brago, King Eternal or sacrificed to Oswald Fiddlebender, though theres some competition with The Birth of Meletis
Its a board wipe you can sequence into or make one sided by playing bigger stuff, it leaves your mana rocks around, it can Lightning Bolt, and it can eventually do a silly-good ultimate ability
For the holos and rares, the raw Youtube data from 9 boxes was as follows (the dashed line showing where the transition from H6 to H5 and from R6 to R5 would occur): image421662 9.75 KB image421787 11.8 KB There isnt enough information to say anything certain about the individual rarities for the holos, rares and Basic Energy cards