I've only had so-so success with that technique on NP's covering, although it depends upon which plane and which covering.

That guide does NOT advise letting the bubbles meld together nor letting the covering come up a bit.

I find that I need to do exactly that to get a good taught covering that will not wrinkle again later.

The "Bubbles over the sheeting" heat setting is exactly what I am looking for.

If I fear that there may be adhesion problems I go over the covering with a slightly colder iron later.

Your results may vary.

In any case NEVER forget about the possibility of warping the surface in all of this, else you will be kicking yourself for doing so.

Hint: With Nitrplanes covering...

Top Flight Clear Coat is your friend.

Use it ( or something similiar ) or loose your covering in a short time due to fuel attacking the adhesive and seeping in, causing all of the covering and trim to let go.

It's a cheap fast safeguard.

Apply several light coats on your finished plane with any and all clear plastic parts removed.