Oldie Genius 300

[phebe1]

I've completed the crossword except for the two unclued questions.
the clue is 'a designation' I have t?r?e h?n?r?d which appears to be 'three hundred' the letters are correct. then the letters belonging to the designation must appear in 35 other squares in another form?? (the old brain isn't what it used to be) any suggestions much appreciated

[Otleybard]

If you shade in every square containing the letters of 'three hundred', a pattern should appear...

I'm glad somebody else does the 'Genius'; it's the one I most look forward to every month. I've always managed to finish it, though I usually struggle with the 'Moron'.

The problem with asking for help with it on here is that it'd usually take 1,000 words to explain its various premises to anyone who hadn't already completed it!