Struggling, finally level, use two rooks, queen and king perhaps? (6)
I believe the answer is:
rulers
'queen and king perhaps?' is the definition.
'struggling finally level use two rooks' is the wordplay.
'two rooks' means two replacements for 'rook'.
'struggling' indicates an anagram (I've seen this in other clues).
'finally' indicates one should take the final letters.
'rook' becomes 'r' (abbreviation in chess).
'rook' becomes 'r' (abbreviation in chess).
The final letter of 'level' is 'l'.
'l'+'use'+'r'+'r'='luserr'
'luserr' with letters rearranged gives 'RULERS'.
(Other definitions for rulers that I've seen before include "Strip with straight edge to measure" , "Heads of government" , "Straight sticks for governors" , "Kings, queens, presidents etc" , "Those in power" .)