I agree, warm white might be more realistic for top part of flame, although yellow is not far off (but amber/orange less so). I lit up a few different candles, noted blue base section but it was barely visible, not nearly as much as your image (birthday candle?). Unless you want an absolutely accurate reproduction, blue can probably be dropped, leaving the pale inner core and bright upper part.
Might be possible to modify colour on an otherwise good design by changing LEDs, but may have issues with vf and current differences between yellow/amber/orange and white, which in most cases not likely modifiable.
Some cheap candle imitations overdo the flicker depth as if in a drafty location.
So where does that leave things: need to find a really superior imitation product, or invest in a custom solution. Might be a market for this for usage you mention, maybe more generally depending on cost.
Dave