Here is a link about bullet rates and twist. For a 1 in 9 twist they show a max bullet weight of 73 grains but that is not a concrete #.
http://www.6mmbr.com/223rem.HTML
From just looking at numbers IMR4895 or H4895 might be a good choice if you don't have powder. As another poster indicated Hodgdon shows H4895 is acceptable for reduced loads
and some of the listed loads start charges of IMR4895 are closer to the velocity you are after.
Note: Hodgdon 4895 and IMR 4895 are different powders and require different (but close) load data.
IMR 3031 and 4064 both show vels in the range you are after but I have not used those powders either. (not much help here)
BLC(2) in Lyman shows lower vels for a start charge as well but Hodgdons site shows higher #s and my results with BLC(2) seem to be closer to Hodgons numbers.
My Mini does not seem to show a Preference between 55gr and 62gr bullet weight when shooting "plinking" type FMJs, and in general the loads for the 62s will be a bit slower velocity wise.
So I would look for 4895 (either flavor) 3031 or 4064. Maybe some others will chime in on their choice given the lower velocity requirement.
Most of us in general tend to be looking for a powder that meters well or has the best accuracy or the highest velocity.
Since you are starting out you will also need all the equipment to load. There are good lists on this site.
Don't forget you will need a way to trim the .223 brass, and if you have brass with crimped primers a way to remove the crimp.
I have both Lee and Hornady presses and am happy with both. When starting out I feel Lee is a good choice because their equipment is a little less expensive.
There are some people who don't like Lee equipment but many others who are happy with it.