Some of the confusion is caused by the fact that (at least some years ago,
maybe not now, I don't know) the FAA written (on line) exam for a glider
pilot certificate required one to give the factually wrong answer to a
question about inter-thermal speeds into and down-wind, in order to get the
mark for the question. You had to answer that it was correct to fly faster
between thermals when going into wind than when going down wind. This is
nonsense, but drawing the mistake to the attention of an FAA Inspector only
got his agreement and regret that he could do nothing about it.

The only time head or tail-wind affects inter-thermal speed or the need for
ballast is when the glide is to a fixed point on the ground, either a turn
point to be rounded before the next thermal is taken or a final glide to
landing.

At 02:16 14 July 2015, 6PK wrote:
Ok, I understand the theory behind the use or need of ballasting,
specially
into a headwind.
A recent discussion debated the need or rather the "no need" for any
ballast for a down wind run.
Would like opinions; pros or con please?
Best
6PK