SweetiePie:
I just bought the L-97 irons
Inside opinion from one of the greats on my friends list is w/ the 97s "NIKE 20XI-X RZN(L61+) is cheaper and more consistent than the NIKE RZN Red Balls (L40+)" and then I see top players using 97s w/ balls of 4.6 spin etc. and that might be a choice I will try in the future, once I learn how to adj. the spin dot for that number.
Individual results may vary, natch.
in any case, enjoy 'em.