I tie the leaders on my sinktip lines because I only use 3-4 feet of leader. For that I use a 1.5-2 feet of 12lb flouro and then 8lb flouro. It turns over just fine. Plus if you're fishing it right you're going to get hung up an break some off, or your going to change flies and keep cutting down the "tippet"

As for floating lines, I use a mix of store bought and hand made. In either case you should be able to use a single leader all year, and just change the tippets out as you use them. I use mono leaders, and then change the tippet from mono to flouro depending on if I'm nymphing or dry fly fishing.

My tip, find the end of the taper of the leader, cut it, and put a perfection loop in. Then you can use a perfection loop on your first tippet size, and go down from there.