Matt,

We never have any major issues with the Varley 30 pal, they provide adequate reserve and cranking output for even a high compression YB...

If its for a road car you might be better with a conventional battery in a battery box..

We always fit a 200A anderson plug for parallel connection of either a piggy back battery or jump pack (just in case)....

The beauty of the dry cell is the absence of nasty fluids and fumes and the flexibility of location options....I have mine mounted in the passenger footwell, behind the footrest, this keeps mains cabling down to a minimum and prevents lots of voltage drop....