Using more weight is not the pure BB'ers main goal. It's putting the most tension on the individual muscle group being worked. Which can be accomplished quite well, with a lighter weight, when understanding a muscles true function. It's the direct Time Under Tension (TUT) thing.....again.
If finding a wider grip , for the overhead tricep extensions,makes things easier, than might apply a closer grip to make the triceps work harder with the better focus on that muscle group. Which may require a lighter weight on the EZ/BB/DB. Or whatever you favor. Good Luck.