NEVER ORDERED from them, but came across this site for custom fitted condoms. Anyone tried them?
Condomania Online | TheyFit Sized-to-Fit Condoms
Fit Kit Condom - Custom Condom
As far as regular brands, I have found Trojan Magnums work best for me. I'm just under 9" long (over if really hard), and between 5 1/2 to 6" circum. I have found Trojan XL are more comfortable but have some slippage as I get into anal so I stick with the regular Magnums. LifeStyle XL's work if it's what I have but they are tight. I just found a new brand, HUGE, a a pride festival I went to but not tried them yet as I don't use condoms with my husband (15 years together) just when I occasionally play.
The point of my rambling is that trial and error. I recommend trying and erroring on your own by jacking off with a few different brands. Trial and error with actual partner can not only be embarrassing either way (Bust or slip off) but also potentially unsafe.