For Gemini strike:
-Summon Goggle Golem
-Activate Gemini Booster on Goggle Golem
-Activate Symbols of Duty
-Special summon Darkstorm Dragon
-And use the effect of Gemini Booster on Gemini Soldier
Hope this helps someone.
technically this is incorrect the card states "you can only equip this to x monster" meaning "upon activation" not "this card can only be equipped to x monster" which would make it fall off when the requirements change.
This distinction in wording is common in CCGs and has been applied to yugioh since day 1.
Feel free to go google it to see that I am not full of crap.