The article by Chad Martin is titled, "The Public Nature of Private Industry in Confederate Georgia", Civil War History, Volume 50, Number 1, March 2004. The subject includes men employed in the "government workshops" mentioned by Evans as reserves.

The law of Feb.17, 1864, made young men reaching the age of seventeen eligible for military service in the Junior Reserve for each state. It did the same for men between the ages of forty-five and fifty, who became senior reserves. The law included many of the same exemptions from service that were already in force. Substitution had been abolished two months earlier, but a new exemption for "agriculturalists" was created.

Breaking the quote by Clement Evans into individual assertions, we have the following --
1) "A large proportion of the officers and men in all the reserve regiments and battalions were exempts from the regular Confederate service,..."
2) "Many of them having been honorably discharged on account of wounds or failing health;"
3) "Many others were employes in government workshops, and..."
4) "Some were State and county officers, while..."
5) "Still others were either too old or too young for the regular service."

Here are my responses, point by point --
1) Exempts were excluded by law from membership in reserve organization. Several battalions recruited from exempts entered service from the State of Georgia. These fit the definition given by Evans, but were never categorized as reserves.
2) The only men Evans describes who could be eligible for service in the reserves were those who met the age range requirement. An officer who had resigned or a soldier who had been discharged (and not exempt otherwise) who was between the ages of 45 and 50 during 1864 was required to serve in the senior reserves. All others were excluded.
3) The law of Feb. 17, 1864, was intended to replace able-bodied men assigned to rear-area duities with older men who were not in service. I will quote from the law if you wish to read the exact language. White men employed in government workshops were exempt by law from April 16, 1862, until the war ended. However, these men formed "arsenal battalions" in cities like Augusta and Columbus GA. These were never Confederate reserves.
4) State and county officers never entered Confederate service, reserve or otherwise. Governor Brown repeatedly asserted the right of the State of Georgia to keep state and county officials, including militia officers, out of the Confederate army. If a civil officer such as a justice of the peace or county judge wanted to volunteer for military service, he vacated his office. If a Confederate soldier was elected to civil office, he produced a certificate of election signed by the Secretary of State and received a discharge. Evans knew this from personal experience as a commanding officer. I'm astonished that he would make such a statement.
5) If "regular service" means from age 18 to 45, I guess so.

Please let me know if you have any other questions.