1) if there is more than one page, the second page will be sent in a following message. Check to see if there are any new message.
2)You are exactly right. SH3 does not show the subdivided grids on the map, but basically divide the AG33 for example, with subsections numbered as so:
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| 1 | 2 | 3 |
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| 4 | 5 | 6 |
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| 7 | 8 | 9 |
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The position there dictates the 3rd number (in your example 4), then within THAT grid AG334, subdivide it by nine again in the same way, and that narrows the position right down.
Because of SH3 not detailing the grid to this level, you have to kind of use your imagination and best guess... at least thats what I do for my KTB's
However, this is only my understanding of it, and I may have it totally wrong, in that case, I would be happy to find out the correct method myself!
Cheers and welcome!
Jamie