Yes, brushing it on is fine, as you stated, you'll get it into the cracks well this way, and it levels itself out completely as it dries... it WILL NOT stick to anything though, contrary to what some believe... as noted above, it will flake off shiny surfaces, and will not stick to any plastic, etc. Its sorta like superglue, people stick their fingers together with it and assume it will stick to anything that well, and in reality its uses are quite limited. It sounds like it should work well for what you're doing though.