RE: S-Type : 104 vs 93
We tested the ST104 in slalom mode with 7.5 NC-X nocam freerides and it worked "OK" (probably better for lighter guys like Per at 63kg than me at 92 - and better with lighter nocams than full race sails in 7.5m). 7.5m certainly helped get the ST104 planing earlier in marginal ST104 conditions than using only 6.5m, speed comparison in marginal mode between 7.5/6.5 was pretty meaningless, but once powered, the smaller 6.5m (6.6) is going to be faster and better handling combo on ST104.
The difference ST104 to S95 is influenced by the rail shape/s : in S95 it is very hard and square/sharp, it gives the S95 (and rider) more edge to work with, which translates to more efficency, bigger sail capacity (for a given board size/width) - but also a more technical, edgy ride, especially at high speed thru chop (where the ST is just super easy fast).
For the pure racer, they usually prefer the extended range and accept the no compromise technical nature of the S95 (and similar) - for the fun or free racer, the ST delivers an easier "fast" performance at the mid to top end of the ST's range (thanks to the bevel ST rail) , but compromise a little on the early planing and maximum sail carrying - at least compared to a similar sized Sonic.
Hope this answers your question/s but please let us know if you need more info.
Cheers ~ Ian