What radius of tracks are Hornby curved platform sections for?

Hornby's curved platform sections feature on many home layouts, and although there are arguably more realistic looking platforms available, they do serve a valuable purpose on a lot of layouts that are more focused on the fun aspect. But as they are usually sold as simply either large or small radius sections, many are left scratching their head when it comes to matching them with a suitable curved section of track.

The large radius curved platform section (R642) is probably the most useful. The inner curve of this platform is perfectly matched to a 2nd radius curved track section (438 mm radius). If you decide to use the outer curve of this platform, you will need a 4th radius curve to tessellate (571.5 mm radius).

The small radius platform section (R463) only really has a single useable edge, that being the outer edge. For this, a 1st radius curve (371 mm radius) should be used for a perfect fit.

There is no Hornby platform section to accommodate a 3rd radius track as the space where it would typically be placed (halfway between radius 2 and 4 tracks) is taken up by the main body of the larger platform section.