Titleist will automatically put the heaviest weight in the club to increase the swingweight - without looking it up i assume 19 grams is not one of the options the plud "+6" or 16 grams might be the max they offer. With regards to flex it depends where you cut it, if done on the grip end it won't change things very much - maybe slightly stiffer, if cut towards the hosel it will dramatically stiffen the flex- tour pro's like to "tip their shaft" about a half inch to make it play stiffer. Shaft flex is determined by putting the grip end in a vice and then hanging weights on the hosel end to get the right levels of flex or tolerance to the shaft, shafts that bend more are less stiff than one's that barely move and they are calibrated to be in a certain range to determine flex. You might want to increase the weighy of the shaft to the maximum offeringg - similar to how fairway woods are weighted heavier than drivers.

When a customer orders an club with an adjustment to the club's specs Titleist will not make any assumptions as to swing weight as they do not know the customer's reason for the adjustment. I would always recommend requesting your desired swing weight so they can then advise you if it can't be reached and/or recommend other adjustments to reach your desired swing weight.