Caps for crossover upgrade for Opera Grand Callas Loudspeakers

Hi, first of all excuse me for my English.
I’d like to upgrade crossover of my beloved Opera Grand Callas Loudspeakers
http://www.operaloudspeakers.com/en/collections/callas-line/grand-callas.html
I’ve got a Merging Hapi as dac, Soulution 721 preamplifier and Krell Fpb 400cx amplifier, I use pure Ag Lasound cables (http://www.lasound.it/en/)
Here you could find more information about my loudspeakers.
https://drive.google.com/open?id=0B9kNUs8PnpkEa21XMjRmaE5ZdWs
They use Scanspeak 9700 tweeter from 2khz and above, Seas 6" custom midrange from 200hz to 2Khz and two Scanspeak 8" aluminium woofers.
Woofer could be this, but I’m not sure
https://www.scan-speak.dk/products/prod-woofer/?single_prod_id=157
While midrange is very similar to this
http://www.seas.no/index.php?option=com_content&view=article&id=101:h1520-08-u16rcyp&cat...
Here is the schema of the crossover, maybe it could be quite different, I haven’t yet dismount the woofer in order to take photos, but this schema is taken from the my loudspeakers’ little sisters, the Opera Callas Diva, that are a little smaller and with only one woofer instead of two.
http://i66.tinypic.com/etil95.jpg
And here is a photo taken from Opera Callas Diva crossover.
http://i67.tinypic.com/16blocz.jpg
As you can see, and in this respect I know that it’s the same as my loudspeakers, capacitors used are Mundorf Evo Aluminium.
I’d like to change the 6,8 uF capacitor used for the front tweeter and the 10 uF used as bypass capacitors for midrange in order to obtain e more relaxing and refined sound. I’d like to have more air, more natural and organic sound without loss in high frequencies extension.
I like my loudspeakers very much, but sometimes I found the sound, especially with not perfectly recorded and mixed records, a little bit on the hard side in the uppermid frequencies, especially on female voices.
I think it could depends on Mundorf Evo caps that are known to be a little "nervous", so I think to go for a Jupite Copper Foil Paper and Wax caps for the 6,8uF (eventually with a Duelund Silver 0,01uF bypass) and maybe a Jantzen Alumen ZCap for 10uF midrange cap, I know it could be better to use another Jupiter Copper for midrange, but I don’t know if there is enough space for it.
Have you any suggestions?
For midrange caps what do you think of Jupiter VT? What are the differences between Jupiter VT and Copper Foil in terms of sound? And between Jupiter Vt and Jantzen Alumen Zcap?
Thanks.