The heavy leader and orange section should not scare fish.
What you want to do (if I'm picturing your system correctly in my mind) is add a length of monofilament leader to the orange section. When your leader is complete, including tippet, the orange section will be roughly in the middle of the leader or closer to your fly line. I like my colored sections (called "sighters" these days) about one to two feet below the end of the fly line.
Tippet length is up to you and can depend on a variety of issues. I usually use about 2' of tippet when nymphing. For stream trout fishing my nymph leader is usually about 8 feet and built something like this:
~ BUTT: 2' of 30lb test
~ SIGHTER: 1' of 30lb test
~ MID SECTION: 1' of 20lb test, then 2' of 12lb test
~TIPPET: 2' of 6lb test.