Hi i have stacks of lead tape on my putter and i find it very beneficial. The reason being that once the putter is swinging, it has more weight and momentum and is less liable to track ofline (by tenseness in arms etc). In saying that the general advice is that you should only really have a heavy putter on slow greens. Its all down to personal preference though and quite a few people have commented on how heavy my putter is, but i would struggle to use a putter off the shelf as it would be too light.
My putter is a rosa monza copy mallett putter, and i have lead tape on either side of the mallet. If you are putting tape on make sure it is equally distributed on either side- for balance.

Good luck

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