Granny Scuba, the best way to decide what it is that you need is to define precisely what functions the item needs to serve.
1) Indicate to the boat where the divers are.
2) Allow some "fudging" on buoyancy control at a stop.
3) Be a signaling device on the surface.
4) Lift objects from depth.
The first three functions are easily served by any number of deployable surface marker buoys. How visible they are, and how hard you can hang on them, depends on how big they are; taller and thicker buoys are more visible and have more lift, but are more involved to deploy.
What really concerns me is that it appears that the major reason you want this is because your buoyancy control at stops is iffy. I'm not criticizing you -- I had horrible problems holding stops when I was a newer diver. But I'll tell you from personal experience that it takes pretty darned good buoyancy control to inflate and send up one of these buoys in midwater -- MUCH better control than it does to hold a stop! Now, perhaps your plan is to have your husband deploy it and give it to you to hang on, but if your plan is to send it up yourself, working on your buoyancy control is going to be necessary to do that.
If you decide to purchase an SMB, here are the things you have to consider: Size. They range from three feet to 6, 8 or more. The three footers are commonly used in the PNW, where the water tends to be fairly flat, but may be difficult to see in any significant swell. Small buoys are easily deployed at depth -- Deep Sea Supply makes one that will inflate with less than a full breath! Large ones may require inflation from a low pressure hose, or from a regulator. Which brings us to the second consideration: Inflation.
Some SMBs are open at the bottom, allowing them to be filled easily from a regulator. But if they tip over on the surface, they'll deflate and sink. You can also buy them with a "duck bill" valve, so you can inflate from the bottom but it won't empty if it falls over. You can buy them with ports to attach an LP inflator hose, or to inflate orally, or both. My preference is oral inflation, and I have found the tubes to do that are NOT all made equal. Some are much easier to manage with cold lips than others.
Some SMBS have an overpressure valve, so that if you put too much air in at depth, there is a way for it to escape as the buoy ascends. Others don't have this -- a closed bag without an OPV may rupture if overfilled.
Some buoys come with reflective tape, or a place to insert a glowstick -- lots of features to consider.
But knowing what you want it to do will give you a much better ability to choose what to buy.
