I tried a hot air blower, when I redid the interior with MB-tex.
The plastic becomes more pliable, but the material has a "gauze" backing which I found didn't stretch very much.
On some spots it helped to lift or remove this backing, but I felt the MB-tex then would tear much easier.
Generally, the technique I used was to glue the curved pieces in stages, so that I could clamp it down without any wrinkles.
(Put something flat under the clamps, otherwise they leave a permanent imprint of the clamp in the material.)
The corner pieces at each end of the dashboard were very difficult. The MB-tex would not stretch enough to follow the double (saddle) curvature of these pieces. I ended up inserting a v-shaped piece on the underside of this item.
The result isn't 100%, but good enough for me. Were I to do it again I feel I could do a better job the next time.