I did not get into
how many I could run with the 7.2v battery? 5000mah.
OK, the capacity of the battery is 5000mAh (mAh is milli-amp hours).
Earlier we set the LED current at 20mA, so if we connected one LED to the battery it would run for 5000/20 = 250 hours.
If we had all 30 LEDs illuminated at the same time, the battery would run for 5000/(30x20) = 8.33 hours.
All this is a bit theoretical and those times may (will) not be exact.
The more load you put on a battery, the less useful capacity it will have.
But lets not worry about that.
I do not understand if 30 single led runs ARE the same has 15 dual led runs OR 10 triple led runs?
If they are connected as I showed earlier, yes they will draw the same current from the battery.
A little problem that occurs to me...
When I asked about the LEDs, you said:
The LED bulbs are 5mm and 3mm plastic domed type. the spec says 3.4v , 15-30ma
3.4v sounds about right for a white LED, but other colours red and yellow will have different voltages, and so will need different values of resistor to limit the current.
You may also want to adjust the brightness of the LEDs,
reducing the resistance will make them brighter,
increasing the resistance will make them dimmer.
JimB