If your seeing one lifter gush oil with it at max lift you know they all will, correct
I saw a similar problem on a set of solid roller lifter on a early street Hemi block years ago, the driver side lifter oil galley was machine lower in relation to the main bearing centers witch made the bottom of the lifters expose that oil galley at max lift when running, which made the oil pressure vary at idle
I ended up blocking that oil galley off as those lifters where the good early Engle lifters that had that side(oil galley side) of the lifter body longer than the center side of the lifters.
It sounds to me like you will need a different, longer body lifter or have the block bush and make sure the machine shop has the bushings extend above the lifter bores also to fix it. I don't think I would do that though before making sure I couldn't use another brand of lifters to cure that problem
Another solution could be to have that camshaft reground to lower the heel of the lobes, like a small base circle grind, which will lower the lifters in relation to the lifter bores which might cure your oiling issues
Good luck either way, let us know your solution please