TWL Weight Mod question

I have put a couple of lead fishing weights on a Rega arm with an Ortofon VMS 20E Mk11 cartridge,it sounds great except that it has a low cartridge resonance-around 7 Hz,should I persist or desist with this?
A RF of 7 Hz will only be a problem if there's some energy source near that frequency to provoke arm/cartridge misbehavior. I don't believe 7 Hz warps or footfalls are particularly common.

If you want to raise the RF slightly you could try some lower mass weights. Otherwise, if it sounds better with the weights than without, I'd say enjoy.
This HiFi mod is not designed for use with high compliance cartridges, as it is not needed with them, and can cause mass/resonance mismatches.
The cartridge for some reason seems to match the Rega arm.I did a search on the Ortofon VMS 20 E Mk11 and a lot of people remember it fondly,I think one of our members Quadophile uses one.It is believed to be better than the current MM's Ortofon produces.Anyway it is actually a moving-iron type with the pole piece that comes directly back from the cantilever creating a voltage output by altering a stationary magnetic field i.e Variable Magnetic Shunt(VMS).Thus I believe it is less susceptible to spurious resonance than more traditional designs which rely directly on moving mass to create a voltage output.
I have just added the paper clip,for tracking weight fine-tuning,and low and behold it works with the Ortofon!It seems just as responsive as the other one modded,resonance around 12Hz,which is more typical.I think it has something to do with the way the cartridge is constructed as I alluded to above.
I'm glad to see Paul's paper clip VTF mod still finding happy homes.

I am confused by one thing though. You originally said you had a RF of ~7Hz. Now you say it's ~12Hz. What has changed to cause such a large shift? Adding the paper clip shouldn't do that.
Er, I did say I was confused. Now you know I was telling the truth!

What cartridge are you using on the arm that resonates @ 12Hz?
The cartridge is Linn K18 Mk11 which is now discontinued but was a very well-regarded MM and I think that the old Ortofon VMS is showing it up.