Hi tripodquest,
Just for grunts, I put myself in your position and searched B&H for ballheads that might meet my minimum standards with a price of under $100. I cannot vouch personally for any of these, but would give them a shot.
Here's what I looked for:
1. Separate controls for tension, ball lock, and panning.
2. Arca Swiss compatible clamp/plate
3. Weight capacity of at least 12 lbs.
4. User reviews are taken with a grain of salt, with those mentioning what I'd consider relevant details in the use of the head given additional weight. . . call me a snob, but user reviews from beginners aren't usually worth very much, but if they're positive, then obviously nothing catastrophic occurred, and adds to a positive impression overall.
Heres what I found. . .in no particular order
1. Smith-Victor BH5 -- $49.95 -- At 1.2 lbs, it's a little heavy, but it's a medium sized head with a weight capacity rating of 29 lbs. User "cons" are mostly details that don't alter the functionality, and most seem easily correctable with some imagination. It has a 3/8' mounting hole to the tripod, so if you legs need 1/4-20, you need to get a 3/8 to 1/4 bushing in addition.
Smith-Victor BH5 Metal Alloy Ball Head 700346 B&H Photo Video
2. Giottos MH-1302 w/ MH-655 Quick Release -- $99.48 -- A lot lighter 12.5 oz, but also has a lighter weight capacity (13 lbs). This is a very lightweight head, but would probably work for you. . . just from specs, it's possibly marginal. Giottos is an established mfg, and is probably the oldest of the Chinese photo gear mfgs, so support in the US is probably better than most of the newer companies. I've had a brief play with one of the 13xx series heads in a store and found it felt good. this one apparently includes the 3/8-1/2 bushing
Giottos MH-1302 Pro Series II Medium Ballhead MH1302-655 B&H
3. Smith-Victor BH8 -- $59.00. This is apparently the BH5's big brother. Weighs 1.6 lbs but supports 40 lbs. Heavier duty alternative. Again, you need the bushing to mount to a 1/4- 20 tripod stud.
Smith-Victor BH8 Metal Alloy Ball Head 700355 B&H Photo Video
4. Sirui G-10X -- $99.00 -- This one I have reservation about -- the description says 3 control knobs, but I only see two. . . in the specs, it says that there is a tension control though. This is a very lightweight head at a bit over 9 oz, but the weight capacity is over 39 lbs. This might be exaggerated, but even if you cut the capacity in half, it should be more than enough. Sirui is gaining a good reputation among the Chinese mfgs
Sirui G-10X Ball Head BSRG10X B&H Photo Video
With the Smith Victors, at least a few reviewers say that the panning base is a bit stiff, but this is easily cured by removing the bottom plate and replacing the very thick waxy grease with something like wheel bearing grease -- I've done this on some cheap heads in the past. Also, reports say that the clamps won't allow you to mount a plate from the top. This is inconvenient, but it's easy to see that Arca Dovetails can be filed down a bit at the widest part and retain enough surface to lock the plate very securely. I'd only file enough to allow the plate to drop into the clamp. The one user that said that in cold weather, the clamp would not tighten, but warmed up, it was okay --
This was probably a slightly undersized plate, and the metal contracted enough when very cold that the clamp wouldn't tighten. This may or may not be a single defective clamp, but a slightly longer screw in the clamp or a shim (feeler gauge would be perfect) cut and epoxied to the plate dovetail would cure this. With the low cost of the SV heads, some slight mods could be justified. . . or you could just replace the clamp (and still be @ $100) try some other plates -- the dimensions can vary between mfgs.
One mod I always do is to remove the safety device on the clamps. This allows the clamp to accept a greater variation in plates. I can't recommend that anyone do this, but it's made my life easier -- I use quite a few different brand plates and I've developed the habit of constantly checking my clamps to make sure they're locked down. For Arca compatible clamps, The screw types are usually more universal and will fit any plate, but some of the 3rd party lever plates are adjustable, so can be made to fit any Arca compatible plate, but it's a bit of a PIA to adjust the clamp to fit a lot of different plates, making QR much less so. . .
Two good sources for accessory plates/stuff are OEC Camera and Heijnar Photo
Neutral Density, Filters items in OEC Camera Accessories store on eBay! 3/8 Thick Rails : Hejnar Photo Store, Serving Your Professional Photography Needs
Again, no recommendations come with these -- they're just search results. . .I'm sure there are more on ebay and Amazon. . .and different ones will probably appear every day
Scott