No, I'd avoid adding anything to the beam & tower since you have a dual polarization beam.
If you only had the flat side (horizontal) then I'd say buy a P-500, remove the radials & set it atop the beam, using the beam for your ground planes, but I wouldn't interfere with the vertical beam pattern by adding another RF active element up through it or above it.
I recommend erecting a push-up telescoping TV antenna mast on the other side of the house or yard and try out a
Penetrator or
Sirio Gainmaster (if you can install it correctly - it's a bit fickle but looks less conspicuous because it requires no radials) for local omni vertical contacts.
.
.
.
.
.