Re: custom reticle
If you're using only one rifle and load combination you WILL eventually come up with a thumb rule. I don't calculate wind, I observe and estimate.
On using a custom reticle... you're stuck to that one system, you become a standard unto yourself.
I prefer adjusting the scope or using a standard reticle like the Mil Dot. This will allow you to use anyone's rifle with the "standard" system. Also, it will allow others to spot for you.