Tips;
Paint the manifold to prevent rust under the wrap, also once the wraps on spray it with a hi temp silicon coating to seal it. This will stop movement, and moisture getting under the wrap. This stuff is good for about a tenner on ebay;
Use metal jubilee clips, then you can secure one end of the heat wrap and tightly wrap the rest then adjust if needs be. Cable ties mean you have to do it right first time.
Wear gloves and do it somewhere that
can get covered in tiny little fibres that itch like chuff. IE Dont do it in your dining room like i did in your work clothes.
If you can, wet the wrap as you put it on, it gets a much tighter wrap. And holds much easier so you dont feel like you need six arms.
Avoid kinks as these develop hot spots and try to use a 1/4 Inch overlap. And try and wrap the pipes individually as far down as possible, then overlap quite a bit when you have to wrap a few pipes together.
Finally be very patient, it took me quite a few attempts as i wanted it perfect so i settled with adequate after 2 days of pissing about.