small block adjustable push rods

Is that a good plan?
Will the adjustable section clear the pushrod tunnels, or will you have to install them inverted ? and if you do, what happens if a loc-nut works loose? And then, there's the question of strength, can they take the abuse?
And finally, I assume you are running hydraulic lifters? in which case it won't matter if the valve stem heights vary, because the plungers inside the hydros, can suck up a chitload of variance. That is partly why they were invented. I think the variance would have to be extremely huge, before the lifter runs out of room.
BTW
your lift at the valve is NOT affected by this situation whatsoever, and in a stocker, only you will know about it.