Mark,

any of the Tuvan styles done correctly will
NOT give you a sore throat or be painful.
However, when learning it is very likely
to have things not quite right, so there
my be some discomfort. As your technique
improves any discomfort should go away.
as you said, just pace your self and don't
over do it. Same as any other kind of
physical training, if you push your self
to hard or train in a reckless manner,
you will get injured. train smart and you
will do fine.

As for prolonged medical issues; i don't think
any data or experience supports it. you don't
see higher incidences of throat disease among
throat singers. and any throat disease among
throat singers can be linked to other sources
(smoking etc). That said, if some one has a
preexisting throat condition then some care
should be taken when learning an unusual singing
technique.

you may find a mint & hibiscus tea blend to
be helpful. warm before you sing, iced (but not
too cold) afterward.

hope that all helps.

grover