You're very welcome and welcome to the forum. We can always use more certified mechanics around here to give pointers to those of us that are weekend wrenchers such as myself.
First, I checked my pulley this morning before leaving for work, it is the 3.25" one, not the 3.33" that I mentioned previously.
As far as the Blow off Valve (BOV) versus the bypass valve in my mind the main difference in application is mainly going to be in situations where you have some engine braking - in 4th gear and in the other gears when other than D is selected. (Overrun clutch is only applied in 4th when in D but is applied in other gears when a lower range is selected.) In this situation you've got at least a fair amount of rpms but very little air going through the throttle body. If you have a BOV it is going to be blowing the extra air from the sc into the atmosphere whereas the bypass valve is blowing it back to the intake side of the sc but downstream from the MAF. The MAF is the critical item here as with the BOV it is reading the air going into the engine plus what is blowing into the atmosphere, with the bypass valve it is reading what is going into the engine, (although there will be some transient error which will be pretty well accounted for by the short term fuel trims). With the BOV the MAF is going to be reading high and the long term fuel trims for the mid and high rpm but low manifold pressure fuel trim cell are going to be driven to large negative values. I'm not sure though if that is a problem - I've never tried to tune an non-bypass valve engine. Thanks to the segmentation of the fuel trim cells it may be a non-issue for the most part.
As far as the meth, it is usually best to run it between the sc and throttle body. The meth can be a bit unfriendly to some parts so no need to get it into the sc, and it is at least as effective in cooling the intake charge when sprayed downstream as well.