Hope this may Help
https://www.rtbb.com.au/?s=plunger+spring Data East / Sega / Stern spring tensions & color code:
• 266-5001-02 red .042 inch wire (high tension) Used on games with long shooter lane paths with ramps
• 266-5001-03 black .037 inch wire
• 266-5001-04 green .035 inch wire (low tension)
• 266-5001-05 blue .031 inch wire (low tension)
• 266-5001-06 yellow .047 inch wire (highest tension)
• 266-5001-07 orange .038 inch wire (medium tension)
• 266-5001-10 purple .040 inch wire
Williams ,Bally /Gottlieb
• 10-148-1 Silver 033 inch wire diameter ( common Medium tension)
• 10-148-2 Red 042 inch wire diameter. (High tension)Used on games with long shooter lane paths with ramps
• 10-148-3 Blue 038 inch wire diameter ( High tension)
• 10-148-4 Green 0.035"wire diameter. (Medium-high tension)
• 10-148-6 Brown 026" wire diameter. (Lowest tension)
• 10-148-7 White 028 inch wire diameter.( Medium / Low tension)
https://www.marcospecialties.com/pinball-parts/10-148-XX