The ones we use in our bibs and shorts are a Coolmax pad that would be considered midweight. Some of our customers have called it thin, but compared to the thin pads of 8-10 years ago (smooth pseudo-chamois fabric with virtually no padding), it is not even close to that thin.
I offer a $5 discount code to some of the other bikeforum boards and can offer it here too if interested. Just type TFCZ in the promo code box and $5 will be deducted from the order total.
Dan