Indranil
Your experience is an exact replication of my results. The silver in the main was excellent but when I added the four golds in the rails, the overall sound was way too warm with a loss of upper mid-range detail for my tastes. It was warm to the point of getting a little muddy.
I would recommend burning them in for at least 30 hours before you start making any decisions. Like I said above, whether your burning in tubes or fuses, after about 30 hours of burn in, you'll have a pretty darn good idea what they will ultimately sound like.
If after 30 hours of burn in, you still don't like the sound, try replacing two of the gold fuses with your original fuses. So, each rail side L & R will have a gold fuse and an original fuse. That sounded better to me. Now I have a silver and a gold on each side of my rails, which is a very nice balance. I see where you can't get silvers anymore, so hopefully the gold & original combo will work well for you.
If you somehow can get a couple of silvers, if possible I would only buy two and do a silver and a gold combo in each side of your rails. Four silvers in the rails plus a silver in the main fuse might become too bright rendering details like female vocals and brass instruments a little harsh. Too much of a good thing.
Do you have any tube equipment in your set-up?
Just remember it's not whether you have all of your fuses upgraded or half of your fuses upgraded. If you like the resulting sound, you're the big winner! So then just sit back and enjoy the music.
Toolbox