Ma used both & at some point switched from one to the other likely for money rather than a function problem & she did not use both at the same time but there is no problem doing just that. not sure of a part # & if you make one you'd need material real thin as any thickness reduces the amt of tang/intergear contact (plus increases play from the lesser engagement) and 2 deg of play there will allow up to 4 deg of cam phasing variation & you'll see it as "spark scatter" as in the light dancing on the dampener. Any possibility the oil is dripping from the 2 drain holes in the dist? You might drive out the roll pin/remove plastic collar & add speedway motors shims to reduce the axial clearance to .005"