Parking long term with slide out "almost out".

We will be living it over the winter(in west/central Oregon). We are under a roof built for a 5th wheel, so the side supports prevent us from extending it fully.

I should have been a bit more clear with my post. Will not extending it fully damage the rail system?. Seems to me that if it's not fully extended, there is less overhanging the side and there would be less stress on the slideout. We can deal with it not being sealed by sealing it in other ways.

Thanks!

Brad