Can gel stain be used

We’re not too familiar with Gel Stains so I’m not sure how to answer that question.  I would probably recommend sticking with stains that are specifically designed for log homes and are designed to be extremely breathable.  You need to remember that logs are generally much thicker than boards and therefore can absorb much more moisture, especially in more humid climates.  And that moisture needs to be able to escape.  Many stains tend to be thick and provide a lot of protection, but you can get peeling and rot starting beneath the surface if they don’t breathe well enough.