Assuming you're using conventional gear not spinning.
I'd tie on twice the length of your rod plus a fee more times around the spool worth of mono. Uni to uni for the connection is fine, just make sure it's tightened well and trimmed back on the tag ends.
Lots of ways to rig up. I generally make a loop at the end of my mono leader about 10-12" long and tie two regular overhand knots aka Surgeon's loop.
http://www.animatedknots.com/surgeon...matedknots.com
Slip sinker on by placing end of loop through eye of sinker then around bottom and tighten.
I fish with my own presnelled hooks and snafu rigs which have a loop in them:
You basically "pinch" or fold the line of the Surgeon's Loop about 3" above the sinker:
This now formed loop goes inside the loop of your presnelled hook or rig:
Now run hook(s) through the pinched loop and pull snug while still holding on:
Take sinker while holding on to the loop and make an overhand knot around it with sinker&Surgeon's loop:
Tighten and done.
Height of rig will depend on where you're fishing. Sometimes higher is necessary.
One of many ways to rig up. Try a few and go with what produces for ya
