Kevin, why do you want a vernier sight to begin with? Do you plan to shoot 200 to 1000yds with your rifle? If so, then this sight has plenty of staff:
http://www.trackofthewolf.com/(S(etxvi245loxzuwffosjdpdaq))/categories/partDetail.aspx?catId=14&subId=167&styleId=770&partNum=RS-CREED-3-WEbecause it has both elevation and windage adjustment, plus enough elevation for 1000yd shooting
If you are serious about shooting long range, then you might want to spend the $190 for a Pedersoli Creedmore sight.
Anyway, vernier staff sights are mounted on the wrist of the BC's using wood screws. They have to be mounted PERFECTLY vertical to the receiver and centered to the front sight. Otherwise, your POI's will be to the left or right because the rear sight is canted. You can slim the base to fine tune the vertical position.
The factory Lyman globe sight can be left on because you have plenty of elevation adjustment with the vernier.
Words of Heed: Unless you know how to read a vernier sight, you will be totally dissatisfied with it shooting multiple distances with accuracy. Plus to derive the MOA settings for specific distances - a chronograph and trajectory software will be needed