Barleywine and Polish-style Pilsner huh.
If I were you - I would go with the Pilsner for the day I do your demo brew. A Barley wine is a lovely thing, but it is an extreme kind of a beer, right on the limits for your (or really for most people's) system. We can make one, but the things you learn wont be about how your brewery "normally" works - I suggest a more standard kind of a beer, then you will get to see how the system usually works and get a feel for what to expect next time.
And of course there is the fact that Barleywines take a good several months at least before they are ready to drink..... do you really want to wait that long to try the first beer from your new system?
Polish Pilsner - 1st: do you have the means to do a temperature controlled fermentation? If not, then summer is a bad time to be trying to brew a lager. Its just not going to work. If you do have a fermentation fridge or similar... Lets brew one. Tell me about the flavours. Strong Malt character, sweet? dry? Bitter? Hoppy? what kind of hops do your reckon? Its not a "standard" style so I'm going to have to go from scratch for the recipe (unless you have one??) Maybe give me a brand name or two and I will see if I can buy one to try out.
Anyway - give me your thoughts on the choice of beer and PM your e-mail address so we can sort out some details.
Thirsty