2 1/2 to 2 3/4 inches from the toe.
It may not be that "cut and dried" - I dug out several here - the only lever actions are a 22 Magnum Ruger 96 - the rear stud does not appear to be factory - installed at 1 1/4" from the toe - looks "wrong" to my eye, although probably would work fine. The other lever action is a made-in-1955 Model 94 in 30-30 - it has no studs on it.
Several bolt actions have the studs, that I think are factory installed - a Ruger 77 Compact and a Savage Axis II are at 2 1/2" from the toe. Up to a Parker Hale Model 1200 and a Schultz and Larsen Model 60 - both of them at 3 7/8" from the toe. In between, a Win Model 70 Sporter Magnum is 3" and a Husqvarna 4100 is at 2 3/4". So, of the six centre fire bolt actions that I measured, three are within that 2 1/2" to 2 3/4", but three of them measure to be longer than that. A made-in-1983 Winchester Model 70 "Westerner" in 22-250 does not have any studs. See Post #7 - likely a good reason to be longer, rather than shorter, measured from the toe.
Is several that I had got that were obviously home done - really poorly done ones are "tilted" - not in-line with, or parallel to, the vertical centreline through the butt stock. I think they also should be at right angle to the surface that they meet - in other words, sitting "square" to the wood surface, not necessarily "square" to the bore line. There are a few recessed button type here (flush cups ?) - no guts, yet, to try to install them - I suspect getting them in the correct place, and square to the wood, will be pretty important.