Converter Upgrade Question

[Ensign]

Last week I installed 6 new Trojan T-105 batteries wired in series/parallel. Now I want to upgrade my converter/battery charger. My question is, what size (amps) should I get? I've pretty much decided I want to go with an Intellipower unit with the Charge Wizard. I currently have a Magnetek 7345 unit.
My total 20 hour amp hour rating is 675 AH.

Using the rule of
Charge Rate = "Capacity"�/10 where Capacity is in amp hours I need a charger rated with around 67.5 Amps ( 675/10=67.5). The Intellipower units come in 60 & 80 Amp versions. I am thinking the 80 amp unit would give me maximum charging current when I am plugged into shore power or running my generator. Many time when running the generator there will be other 12v accessories on sucking down my available amps, thus my reasoning for the 80 amp unit.
Assuming my batteries are dead and the converter is putting out it highest voltage (14.4v, 80 amp current), what size wire do I need? Currently I have 6 AWG going from the terminal board almost all the way to the batteries. Right before the batteries there is a circuit breaker and a kill switch where the wire is reduced to 8 AWG. Should I replace this wire with 6 AWG if I get the 80 Amp unit?

Are there any other factors I have not considered?

[Ensign]

Last week I installed 6 new Trojan T-105 batteries wired in series/parallel. Now I want to upgrade my converter/battery charger. My question is, what size (amps) should I get? I've pretty much decided I want to go with an Intellipower unit with the Charge Wizard. I currently have a Magnetek 7345 unit.
My total 20 hour amp hour rating is 675 AH.

Using the rule of
Charge Rate = "Capacity"�/10 where Capacity is in amp hours I need a charger rated with around 67.5 Amps ( 675/10=67.5). The Intellipower units come in 60 & 80 Amp versions. I am thinking the 80 amp unit would give me maximum charging current when I am plugged into shore power or running my generator. Many time when running the generator there will be other 12v accessories on sucking down my available amps, thus my reasoning for the 80 amp unit.
Assuming my batteries are dead and the converter is putting out it highest voltage (14.4v, 80 amp current), what size wire do I need? Currently I have 6 AWG going from the terminal board almost all the way to the batteries. Right before the batteries there is a circuit breaker and a kill switch where the wire is reduced to 8 AWG. Should I replace this wire with 6 AWG if I get the 80 Amp unit?

Are there any other factors I have not considered?