re-thinking dual battery placement

[Illogikal99]

Greetings! I'm a long time V-20 owner and a brand new member. I have been planning to move both my batteries from the transom to a set of storage seat risers up forward under the captains and passenger seating. My reasoning for doing this is that this boat has been rebuilt with a custom heavy duty full transom, large Bracket with a 225 mounted on it and a 15hp kicker... Needless to say, this boat is stern heavy. 120 lbs off the stern would definitely help my situation! Ok here's the question, has anyone wired starting batteries that far from the motor and what if any negative issues may arise from this setup? Would the longer run of cable mess with the voltage output while starting or the motors ability to charge the batts? Any thoughts/ideas are always appreciated,
Thanks,
-J