Your soldiers should be equal to 30-40% of your working population in peacetime to maintain order without making the population unhappy. For you, 30% would be 86 soldiers, so you can decom to that amount. Also, I would highly suggest that you stay in Defcon 5 on any day you collect, and remain in Defcon 1 on any other day. This is to maximize the economic benefits while getting as much protection as possible at all other times. Also, a good way to grow your nation is to tech deal or get new member aid, both of which VE should have available to you and should be pursued.