To increase current capability, transistors can be paralelled, but they need to be h21 matched. To lower the effect of not matching and to equalise currents flowing through transistors, you need to put a equalizing resistor series with emitters.
Choose resistor values as small as possible for lower wasted power.
To take effect, voltage drop across equalizing resistors should be comparable with the transistor's Vbe.
Resistors value depends on the current flowing through them, which depends by the number of the paralleled transistors.
I think, in the schematic you posted, you omitted to draw the inductive load which you reffer in text, and you drawed only a 0,6 ohm resistor. In my before reply, I added to your schematic the equalizing resistors, without correcting this issue.
I think that the completed schematic looks like in <555timer2.jpg> attached, or not?