Whilst all this theory makes sense ---- to some, my
glider manual only has the single polar curve which
itself is a guestimate from a comparison flight with
a 16 metre Standard Cirrus B

I like to keep my flying simple, John Delafields method
works it is simple and in flight uncomplicated. I
suspect the savings on drag produced by speeding up
or slowing down with flaps in a negative, up, position
is relatively small.

Whereas putting flaps down at speed to slow down appears
very inefficient.

Still if you are happy with this loss of energy then
fine.

Dave Martin