I am confused as to the role of the Connect in this. Can't you just take the optical output and plug it directly into the Playbar?
I think @jwagner910 is using the connect:amp (or connect) to wireless send a signal to the playbar.
First, I'd say that this isn't the recommended way to set this up. The best audio you can get from this is stereo audio, so you aren't really utilizing the full functionality of the playbar. You're also introducing a slight delay between the audio and video in this method. If it doesn't bother you, not a big deal.
So, sticking with this method, you could look at changing the compression method to remove dropouts.
https://support.sonos.com/s/article/1080#compression
And since it's outside, there may not be too strong of a wifi (or sonosnet) signal out there.
But, as an alternative method, you could look into wireless hdmi to transmit the hdmi signal from the projector to the playbar. and then a hdmi switch that can outout optical for the playbar. That method would not need a connect or connect:amp to work and should elimate dropouts and any delays.
Personally, if it's at all possible, I would wire the connection. Long lead cables are pretty easy to get, and often aren't as intrusive as they may seem. And I'm assuming you have to setup the projector, screen, and playbar everytime you use it, one extra wire isn't going to be that much of a setup burden.
Danny