I just replaced worn yellow top Optima with a Big Crank ETX30L AGM battery. Its the same case as a B3121 AGM and less than half the price. It also compares to the Odyssey PC 925. It was $113 shipped and its supposed to be made in the USA.
https://www.batterymart.com/p-Big-Cr...L-Battery.html
I re-ran new cables with my East Coast mini alternator and its been perfect at the first two events I've attended.