Wow you guys have been busy on here!... Lee, you're getting good press from my post. I hope I can still source chestnuts from you and they're not sold out!... Maybe I should have kept my mouth shut!

I'm looking forward to trying the chestnut meal you sent.
In any event, I have a chestnut black lager and a chestnut double IPA in fermentation now. They both look tremendous. The black lager has a touch of sulfur on the nose, but it has only been in fermentation for a little over a week so I'm hoping that clears up. I'll transfer the ale to secondary and dry hop in a few days. Fermentation is still going pretty strong at 65 degrees on the ale.
I do have a chestnut recipe for what I thought was going to be an "american cream ale", but that turned out more wheat-like or more specifically like a Belgian wheat kind of like a Leffe. I used 5lbs light roasted chips and a bit of sorghum for that and noble hops... plus the obligatory corn sugar to get it up to OG. It was a bit too hoppy for the style, but other than that after the harsh sorghum flavor wore off in a few weeks it was very good IMO.
If I was modifying it for a Leffe or Duvel-like beer I'd probably keep the chestnuts the same and just drop way down on the hops. If I make another "cream ale" I'll use less chestnut chips and probably drop the sorghum to get it lighter in body. The 5lbs of chips give the beer a weight.
Regarding yeast, I use mostly SafAle and SafLager yeasts for GF because they're supposedly grown on beets. Most yeasts are not GF, so you have to be careful if you're making it for a celiac or a celiac might drink it. I'm just intolerant to gluten so I could do the other yeasts, but who knows who else would want to drink it and it's a small sacrifice...