Brewers Friend app estimated OG of 1.098 based on the ingredients listed, however as I held back 500gm DME until 5 days into fermentation, I made a rookie error and didn't take a reading before pitching (i.e. assumed I wouldn't get an accurate reading given not all ingredients had been added at that point).
This is the first time I've done such a big beer, and as I usually keg, I'm just trying to make sure I'm not going to bottle too soon.