Thank you! These are the details and current resolution.
I) The two 2006 SR 340 SDA I'm familiar with have Progressive Dynamics PD-2040 converter/ chargers as OEM with 4 LA batteries group 27.
II) Asked service manager at Sea Ray for opinion. He said" All boat manufacturers are recommending upgrading to AGM batteries albeit expensive. Most onboard chargers have settings for LA, Gel, AGM. Make the setting change if available."
III) The PD-2040 does not have settings to change. I emailed tech service at Progressive Dynamics with all details of OEM and proposed AGM batteries.
IV) PD responded next day "Hello, No problem at all. You will get a full and complete charge into your AGM batteries. Thanks, Andy". Hope this helps others. Will share any future issues.