Pulling does not change the EI of your film (by much, anyhow). It lowers the contrast by reducing the negative density vs. normal processing, with the degree of this effect varying proportionally with the amount of exposure each part of the composition has received.
If your film is ISO 100, and you want to get shutter speeds of two seconds on a bright and clear day (assume EV 15), all you have to do is some basic photographic figurin'. First of all, what is the equivalent exposure at your minimum aperture given EV 15? EV 15 = sunny 16 = '125 at f/16 = '30 at f/32. How many more shutter speeds do you need to cut to get to two seconds? First of all, consider reciprocity failure. With a conventionally-grained film, let's assume that when an exposure of 1 second is called for, you need to expose for 2 seconds due to loss of reciprocity. So if you are aiming for a two second exposure, you actually only need to count down to one second: '15, '8, '4, '2, 1. Five shutter speeds. (In an ideal world, you would have an ISO 3 film for this exposure.) Your filter takes care of three of those five stops. You are left having to overexpose by two stops. The fact that you are using negative film will let you print through at least one stop of this easily without a major change in contrast. There is also the very likely possibility that your working EI could be lower than box speed, and if so, that reduces your overexposure even more, making it so that in the end, you need to contend with possibly under one stop of overexposure in order to get a decent neg (not a "perfect" neg., but certainly a fairly easily printable one). You can surely use your X-Tol to pull a stop or so.
In short, I would do an initial test by making the exposures at 2 sec at f/32 with the ND filter in place, then cut 25 to 30 percent off of your normal development time and see what happens. I have never pulled with X-Tol, but it can't be all that different from most other developers.