If you are looking for the highest possible protection, you can consider registering each version of your logo separately. Each of your logos will be trademarked individually and will receive a certificate.
A downside of such a registration might be the cost. In case you have three different logo variations, you will be required to pay the government fees three times, as you will need three separate applications.
If you don't have enough financial funds, you can consider registering a version of your logo that you use the most in connection to your goods or services. This registration will protect you against anyone using an identical or a confusingly similar version of your logo.