I lumed over the Yuki lume. The lume mix I use somewhat masks the original dial lume but still glows. This would be period correct for mid 60's tritium dials as those dials still glow due to the phosphorus content used in those days.
If this were a '70's dial, I most likely would have painted the lume plots first with an opaque flat white prior to luming.
Removing the existing lume is not an option. Frankly not worth my while. The Yuki lume is a white resin. it's very very difficult to scrape off. It can be done but I would charge too much for that process which would result in very little additional visual benefit. It's a rep dial... Be as cost efficient as possible. A gen dial is a easy future upgrade if/when a reasonably priced one pops up.