Rio sells a premade leader with a light shock gum section already in it.

Personally I boil my leaders for 7 minutes to soften them. After boiling a leader it becomes super soft but not to the point of shock gum. I'll generally use a Rio 12 foot leader and then attach a short section of tippet to the end.

If you are fishing a lot of light tippet (ie 6X-8X) boiling your leaders is a must. It is stealthy, the soft leader casts much better, and it has a lot less coiling than a stiff leader so it floats for dries or indicators much better.

John