Hm, thanks for the answers. Couple more questions...

1. Why the "taboo" of using indexed shifting? Is it generally just known to be worse than friction? I always thought index would be better because you could mentally known how many gears you've moved by the clicking sound or clicking "feeling" in your fingers.

2. What if I use 7402 downtube shifters, will indexing shifters meant for 8-speed SIS significantly improve the performance or otherwise work better?