[TuRo]

Tbh, if beefing-up an oldie 34mm with a 78350, I've found 357 and 557 fit pretty much anything (6426/6694/manual 34mm Rolex say, and all Manual 34mm Tudors and auto 34mm Tudors 1940/50/60/70s) with a bit of remodeling around a thin nosed pliers to widen them or close them which moves the hole line up as you do it.

Wider you make them then the hole line up is inwards toward watch and thinner you make them brings the hole line up away, but of course flattens the end links a tad so not always 100% filling the aperture (i.e. tiny gap at top of end link).

Tudor Oysterdate 34 came in both 19 and 20mm lug widths of course and you obviously have the 19mm.