I cant speak to that particular lamp
But as to scotch tape it works quite well, the matte tap diffuses the light quite well
But be aware that it might also change the colour of the light a bit … On a fenix hl55, the light became cooler
There is also a popular window film called dc fix that you can use
As to warmer vs cooler white … Its honestly doesnt matter to me
With the lumens a good 18650 lamp is pumping out, when you need to see well you just pump it to 800+ lumens for a few seconds anyways … I actually prefer a cooler white myself
Keep in mind that petzls are mostly cool white and sponsored skiers and climbers with those do crazier things than anybody here at night
One consideration for flood lamps is to ask yourself how much do you need to look at your feet … For night climbing its very important especially on vertical technical terrain … For this a somewhat floody lamp is important so you arent aways staring down (which also bumps your lamp/helmet/head against the rock)
If you need that peripheral vision awareness of light at your feet then a floody lamp or the scotch tape fix would be useful
This is more important on technical terrain
Of course you give up a bit of throw useful for routefinding purposes
;)