Comparatively thin, metallic bar running through deck (7)

I believe the answer is:

tinnier

'comparatively thin metallic' is the definition.
(tinny can describe a thin, metallic sound quality)

'bar running through deck' is the wordplay.
'bar' becomes 'inn' (I've seen this in other clues).
'running through' is an insertion indicator.
'deck' becomes 'tier'.
'inn' going into 'tier' is 'TINNIER'.

I've seen this clue in The Times.

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