Dear Johnny,
HHDL visit will most likely affect your current members and also new members to come. But that is temporary. Ultimately whatever HH might say during his stay re Dorje Shugden will not be heard and recognized by all. Also the problem is other dharma centres might use that 'against' you. But if you remain steadfast, then you will overcome. They lose steam over time. In fact good to recommend them to this website. Educate them.
I dont see any use in doing things that your teacher didnt recommend such as protests, as that will bring undue and unnecessary attention to your new centre negatively. Introducing them to this forum and website will help them alot as it has helped me and many others judging from viewership. That would be a good online support for them when your members may have questions and or doubts. Support is a very important factor.
It would be good to concentrate on Dorje Shugden's sadhana more in the centre or individually, do the serkym part as much as possible to increase the centre and to focus on control aspect of Dorje Shugden's mantra (400,000).
I am sure that eventually your centre will grow, expand and increase like all the other centre's that has been started by your teacher. Create the causes for it to increase and it will. There are many who will be affected by the HHDL speech, but there are many more who will not be or hasnt heard anything nor care.
I offer my hearty congratulations to the opening of your centre and I am sure it will grow. Dave, you are courageous and have great conviction to spread the Dharma.