That little 900w continuous genset may be hard pressed to power the b&d 1093. BFL would know, seeing as he has one.
Generally you should balance the wiring. Both the load (out) and charge (in) must be wired to (the same) opposite poles of the bank.
http://www.altwindpower.com/battery-series-parallel.php
4th diagram down.
You may be able to move wiring around to put the two terminals needed more within reach? You may also want to consider hooking up the 1093 with terminal lug rings, instead of clamps, for a more semi-permanent (one time) installation.
