Can anybody suggest which is the best version for (preferablby examinable) 'nest of boxes'

None of the Nest of Boxes are examinable, except one, if you are talking about the very expensive stage versions. There is no reason to have the boxes examined during a presentation in a show in front of an audience.

This Nest of Boxes that can be examined:
http://www.magicgoods.com/products/mystery-nested-boxes.php

This one is similar to the above and can be examined after the trick.
http://www.abbottmagic.com/Abbotts-Nest-......oryId=-1

If you are speaking of the close up Brass Nest of Round Boxes, that Viking and Magic Makers makes, then these can be examined after the trick is presented to their hearts content. These are for the vanish and production of a marked quarter.

Also the Jiffy Coin Trick by Adam's Magic can be examined, and the small nest of boxes that uses a box, and a small match box, can be examined. These use the vanish and production of a marked quarter. a quarter.