Most of your problems are strictly Sailwave issues.
I'll answer your questions from a Rinderle B point of view.
But first, I'm not entirely clear whether the
Rinderle B in Sailwave is actually an implementation of
the formula developed by Colin Burrell in response to
the Denver Sailing Association _or_ the original
lookup table developed by 'Jim Rinderle of Marblehead'
in the early 1980s (any more information, or even a primary
source would be welcome). Your reference to a score of
91.2 indicates the original lookup table
Rinderle B defined all last places as a score of 10.5,
irrespective of fleet size. Since I can't find a
primary source, I'm going to use results from
the Gulf of Maine Ocean Racing Association, who actively
use Rinderle B. Apart from last being consistently 10.5,
the next lower score is zero. This is fine for DNC,
but either GMORA has no OCS, DSQ, DNS etc, or it scores
them zero too. There are no cases of multiple 10.5s
that I can see.
Essentially it seems to me that it is up to you how
you score OCS, DNF, etc. However, scoring them as
number_racing+1 won't get a good result from a
lookup table which finishes at number_racing.
You have to tell Sailwave that this is what you want
through Scoring systems>Scoring codes
1. the score for last, 10.5 is correct.
2. 91.2 is correct from the lookup table.
3. the non-OCS scores should have been
calculated on the basis of a 7 boat race, so your last is
a 5th, as you suggest & scores 36.3. I can only suggest
that there is a problem in your scoring codes.
4. dealt with by someone else I think, but again, a
Sailwave issue rather than a Rinderle B.
5. see above.
6. see above again.
Chipstead High is a much better bet, and, if we are lucky,
will be implemented in Sailwave, real soon now. However,
the real issue is that of understanding the Sailwave
setup, especially the scoring codes. I still don't get
them right every time.