Some users have recently had their accounts hijacked. It seems that the now defunct EVGA forums might have compromised your password there and seems many are using the same PW here. We would suggest you UPDATE YOUR PASSWORD and TURN ON 2FA for your account here to further secure it. None of the compromised accounts had 2FA turned on.
Once you have enabled 2FA, your account will be updated soon to show a badge, letting other members know that you use 2FA to protect your account. This should be beneficial for everyone that uses FSFT.
the difference between 1/2 and 5/8 is barely anything. If you are set on using 1/2 tubing, just dip the tip in boiling hot water to soften the tubing, then slide it right over. You will have a nice tight fit.
I do it all the time to put 3/8 tubing on 1/2 fitting. You can techincally go clampless this route. Just a thought