Oil Pressure Gauge issue

Since my Rallye Dash oil pressure gauge works sometimes I figured I would install a T connector and put a mechanical gauge in and leave the factory gauge hooked up. I got everything installed and the mechanical gauge works great. The factory oil pressure sending unit now interferes with the vacuum advance and the timing cannot be adjusted anymore by rotating the distributor clockwise. I haven't checked the timing yet but I'm not optimistic the timing is set correctly. Should I bag the T connector and just leave the new mechanical gauge in place? I'm sure I'm not the only person that has had this problem. What would you do?