I wired up the two stage grid charger and powered it up.
Put a switch on each of the four 48V supplies, and a master switch that turns on the two CC supplies.
A 6A diode across each of the power supplies output terminals so current has a way to get back to the CC power supply negative when the 48V supply is off.The diode drop about 2 V when all of the supplies are off.

Each of the 48V fixed supplies can be adjusted from 40-53V.

With all of the 48 supplies turned off, we have a 350mA and 700mA CC supply that has 4 diodes in series with it.
This gives us a choice of 350mA, 700mA, or 1050mA.
The current can be supplied over a CC range of ~6V to 46V.( 2V lost in diodes)
A single subpack to 5 subpacks.

Turn on one of the 48V supplies, and we add an adjustable 40-54V
Total CC range ~40V within a range of ~43 to 100V
(Half of an Insight pack)

two supplies ~83-154V (InsightII 100V pack)

three ~123-208V (Insight and Civic pack)

four ~163-262V (Prius pack)

5 or more to do any hybrid battery out there.

The CC supplies work perfectly in parallel, so in theory one could put 10 or more in parallel to get a 6-48V 7A+ power supply.
Lots of possibilities.