Sam from DFH let me try their 61 out of his glass (keg had kicked, and we couldn't order a pint), and it is indeed very much a beery wine. It's 60 min, mixed 50:50 with Syrah must, the juice added in the fermenter once they'd fermented a bunch.
Flavor was a bit odd, but I'd just finished a pint of 120 min, so my tongue was a bit numb from hops to give an accurate description.
I'd treat this just like any other high-gravity beer with post-boil sugar additions; make sure the must is clean (no buggies), and add it in 1-3 portions, depending on amount. I'd try not to go up more than 35 or so gravity points to avoid stressing the yeast, although I don't think I'd oxygenate at must addition.