I have a Dwyer Original and need an equivalent in Stu Millers spine calc program due to Dwyer not being in there. Does anyone think the Great Northern Critter Gitter is a close match up or possibly something else?

Just use the Generic setting for the type of bow (longbow or recurve) you have.

As an example. My Blacktails aren't listed so I use Generic Recurve for them.

That's what I was looking at but with my set up 56@28 with a 29 draw and 455 gr arrow it has it coming in at 205fps which seems like it would be too fast.not sure though, haven't chornoed it.

I also have found that by using the generic option it is no where close to the arrows my bow needs.......

The calc. is pretty close when I use both the generic bow model or the specific bow model I use as long as everthing is entered correctly. As far as speed goes, it is right on for me as I shoot about 170 fps and it says 169.8 fps.