A raw '85 Clemens that appears mint sells for like $10, and SGC 8 sells for around $24 (a difference of $14). So right now you have the $10 card, you'd need SGC 9 (~$35) for the difference to cover the fee. The other players you mentioned likely won't have as high of a difference in price. I don't think grading fee is worth it.
They've been sitting in the box untouched for 30+ years, if you are keeping them then why grade? Why not just put them in top loaders? 100 cards x $24 = $2400 in fees, and in the end you will have the exact same cards you already have. Wouldn't it be more fun to spend that $2400 on new cards?
But your responses seem like you are trying to convince yourself it is worth it to do the grading, so go for it. Perhaps the thrill you experience with grading will be worth it. But maybe instead of sending in 100, maybe just start with 10 and see how you do? Let us know how you make out, good luck!
