I have an opinion about how to get zddp in to your engine but of course I have an opinion about everything.
first off more zinc/phosphorous/calcium is not always better. All known oil educated persons say more that 1400 ppm is worthless and in some cases detrimental.
Second, simply adding a fortifier to your oil is not the same as using an oil like swepco 502.
Others make oil with enough zinc/phosphorous/calcium to exceed any and all necessary engine demands but we'll focus on swepco products here. The chemists that formulate the products do so from more experience then the after market. They are also backed up by literally "billions" of real world miles. Most fortifiers are snake oil with no documented proof that they are what they say. I will refrain from naming names.
People have success using commercially available zddp additives like eos (GM) but that was developed for the mainstream customer who doesn't know how to determine what does and what doesn't have enough protection.
I personally run some flat tappet engines with more spring pressure then god and have never had a lifter problem with any of them and never use an additive other then prelubing the cam with good old black moly cam lube.
Cutting to the short strokes, just use a good oil, swepco in this case and trust the oil to do its job.