Not sure about resurrecting this 3 month old thread, but for what it’s worth, I use Fabsil, but I would bow to the use of Autoglym products as well.
Whatever, my tip is to start at one side at the edge nearest to you (above the door) and work to the middle. Then go around the other side and work from the middle out - avoiding the risk of a ‘dry edge’, if you start at the mild and work towards the edge.
Kind regards,
Gareth.