Frank's (or any other, like Pitbull) C-Belt design is different from a regular belt. On a regular belt, it's just a really wide triangle. A C-belt has a mild curvature to it. So instead of being a straight cut, it's cut on a very mild curve. What happens from that is the top edge of the belt is ~1" smaller overall diameter than the lower edge. Hard to show with ascii text, but basically:
Regular belt profile
| | {BODY} | |
C-Belt profile
/ / {BODY} \ \
The upper edge sitting tighter helps reduce the "belt sag" you get with a regular belt, where it slowly rides down on you. It'll still need to be tight, but less tight than a regular belt. It does still have the potential to fall completely off, since there's nothing holding it in place vertically other than your own girth, and the more comfortable (loose) you have it, the more it's going to want to wander when you move and the chausses weight tugs on it....
I've got a C-Belt by Pitbull, and while I did like it at first testings, it has a couple issues; the biggest is it digs into my thighs when sitting, though I've heard Frank's / Viking Leather's is a softer leather and is comfortable to sit in. As far as pointing for chausses, there's a long thread by Sir Ulrich about it - if you have trouble, post up, we'll help out. Alternative solution below, too.
I do second the suggestion of the pourpoint. It's a later period solution, but it is period - and it's also hidden under everything when all is said and done, so only we know of your sins.
The biggest benefit of the pourpoint vs C-Belt is that the pourpoint is a vest, and goes over your shoulders; it doesn't have a lot of sag potential. It's also a multi-purpose garment that you can use for plate legs later, should you come to the shiny side.
If you want a cheap and dirty "it works and it's hidden" solution, look at the pictures labeled "Fauld" here -
http://james-anderson-iii.com/tutorials/pages/how-a-man-shall-be-armed - it's how I've done my fauld so far with a "cheater harness". I made it from scratch, but if you added X straps to a basic belt, that's all it is. Early transitional armor with just a breastplate (no backplate) used an X strap configuration for the upper straps, so it's quasi-period. The big benefit on this style vs the c-belt style is you don't have the "tabs" of the C-belt, just a simple standard belt that you can punch a few point holes through. The closer you have the X strap and pointing holes together, the better.
Then to actually point the chausses to the belt - for my "stocking" mail chausses, I added a leather strip at the top and I lace them to a pourpoint exactly like with the leather tabs on plate legs:
If it's a combat thing (as you mentioned the clubbin'), the C-Belt will give extra protection on the thighs, and is a wider belt around the back/kidney area. The pourpoint is slightly padded too, but probably twice the cost - so checking the C-Belt first seems like a good option. If you're not happy with it, give some of the other options a try.