@LessStressThanFifa No my friend , don't worry about the bench. What matters most is your first 11 line up.
And be careful with how you will choose your special tactics... If you have a very strict Ref , choose wisely your tackling and pressure etc. You cannot afford to lose another player tonight, from what you wrote here.
"I'm top of the league and closing in on 25 wins in a row between my two careers, to get the achievement so I'll be annoyed if it counts as a straight loss."
Congrats for that , but keep in mind that for this achievement you will need 25 wins in a row from a single league / Slot mate ( including Cup matches ). And not by counting wins from multiple leagues. If it was like that it would be so easy for an achievement .
P.S. Do you have maybe a spare midfielder to place on your bench? Not the ideal thing to place our players out of their rightful positions ...but extreme situations require extreme measures sometimes.