I purchased 10 pound test Trilene FC to use as leader material. What size braid do I use to match? Does it matter? 
 

Thanks. 

It usually works the other way around.

choose your mainline first.

Many rules of thumb are 10#braid on spinning gear and 30# on baitcasters

It is spinning gear and a couple of spin cast reels. So you recommend 10 pound braid to what size FC? I plan to mostly be fish from the bank. 

I'm 15# Power pro to 8# Sunline sniper on spinning and use Alberto knot.

I'm looking at 10# braid on my finesse rig - to 8# leader. Finally learned the FG knot, so that's what I'll be using.

6 minutes ago, TCB said:

It is spinning gear and a couple of spin cast reels. So you recommend 10 pound braid to what size FC? I plan to mostly be fish from the bank. 

The beauty of braid to leader is that you change your leader based on situation.

I use 4# to 12# depending on situation 

So how much does matching diameter matter? Does it need to be exact? 

2 minutes ago, TCB said:

So how much does matching diameter matter? Does it need to be exact? 

If you tried to match diameter, you'd be really off...10# braid is about 2#-4# mono/FC diameter. Long as you use a good knot, the diameters don't have to match.

Not necessary to match diameter as your still contending with a knot, bigger the diameter the bigger the knot. 

So 20 pound braid to around 8 pound FC for clear water? 

I think you would be fine with 10 to 20 lb braid.  With FC I'm less concerned with water clarity.  15lb braid with that 10 lb FC would be a good setup.  Just make a good knot.

As noted here already, keeping the main line & leader diameter size relatively close is a general rule.

However once we get to the lower tests in braid, like 10 lb for example, the braid starts getting super thin; especially these days. 

I fish braid mainlines with leaders on all my spinning gear and have been for a several years.

And while I use mono leader a good bit of the time with some FC mixed in, the premise for me is still the same.

I Start by matching the MAINLINE to the gear I'm fishing - as it relates to line management & casting distance, which is always a factor for me. Then I will select a leader size & material to fit the conditions I am fishing the gear in.

I fish in clear water myself (for brown bass) and will often go with 10 lb braid with 8-10 lb mono or FC leader.  That works for me. I will also use 15-20 lb braid with a 10-12 lb leader depending on the diameter of both lines, still wanting them to be fairly close.

I talk about it here . . 

A-Jay

Don’t overthink it. I use 20 lbs braid on most of my baitcasters and tie everything from a 17lbs leader to a 10lb on it. 
 

For spinning, I use 15lb braid and a 7# or 10# leader. 
 

Tying a great knot is the unlock. I tie a modified Alberto knot (it had a couple additional rotations through the loop at the end) and take my time to wet and cinch accordingly. 

Trilene has two fluoro, the "Professional", and the "Professional XL",  either one's diameter is thicker than other brands'. So the diameter of 10lb Trilene fluoro would be the close to, say, Seaguar's 12lb fluoro diameter.  If you're tying FG knot, the rule of thumb is to have the braid line thinner than the fluoro/mono leader. So, you got a lot of options. I'd say any braid from 8lb to 20lb would be fine. 

What reel are you using? Spinning or casting? What size is the reel? What power and action rod? I'd guess a medium for 10#?

I use 40# or 50# pound braid with a 12-15# fluoro leader on baitcasters, when I don’t use straight fluoro. 40# is a close size match for 10# fluoro. 
 

For spinning I run either 14# Fireline or 20# braid with 8# fluoro leader.