check out the sheet they have posted on here about what the top tactical shooters are using it is really good info. I have a couple of vortex scopes so I am partial to the vortex. If I were to switch to a ffp I would get the HD. Good luck sounds like either would be a good choice.
If you are going to hunt with it alot then I would go with the 24in barrel. If it is going to be used to hunt some but mainly target shoot then go with the 26in. Hope this helps.
I use the accuracy first wiz wheel and there formula. Plus there are shooting simulators that seem to be good and both bullet drop and reading wind. Hope this helps some.