I would pair them with the two new ones as one set and the older ones as the other set, then parallel the two sets as a bank of four when camping.
when not camping I would disconnect the two sets from each other but leave them in their pairs.
I would use the 1093 on the bank of four while camping as needed depending on your usage, length of time away, etc, doing 50-90s or whatever SOC range works for you. 45-85s? whatever.
At home I would use the 1093 on one pair at a time to bring them back to full before going on a float charge or sitting idle. (if sitting idle take the pairs apart so they are separate batteries)
I would equalize each battery separately , not as pairs, but I would only equalize them if their SG failed to return to "baseline" after being charged to full and then put on float for a few days. You can hurt them with too much equalizing.
The 1093 does not do float, so you still need a proper battery maintainer, low amp charger for that or else use your rig's converter if it has a suitable float voltage for the temperature there.
I am unclear if floating each pair separately is needed or if all four can be left on one float charger. The self-discharge the float is meant to prevent would be prevented, but there might still be some funny activity between the batteries in parallel---I just don't know how that really works (or doesn't)
