a-j,
You have the right idea and you have found something that is working for you. Charlie never had any money when training his athletes. People have this idea he was so high tech but his real expertise was in how creative he applied the key principles of proper training. He never had anything fancy to work with in terms of any equipment. It took him a long time to generate money and when he finally did he spent it having people work for him to improve the performance overall for the group.
If you have a stim that is working stick with it.