snap weights

Don't limit your options, but yes-snap weights and worm harnesses are very effective for lake Erie walleyes. You really don't need riggers for walleyes, there are enough other proven methods of getting your baits down into the zone. Dipsy divers, jet divers, snap weights, in-line weights, and deep diving crankbaits are some of the options you might consider.

Time of the year will dictate which tactics are preferable. Early in the season, you can find the walleyes in relatively shallow, say 20-30 ft. Later in the year, the fish will migrate towards cooler and deeper water, anywhere from 70-110 ft depending which areas that you are targeting.

There are dive curves that show how much depth each ounce of weight will add when using the snap weights. I think a rough rule of thumb is that each oz of weight will add 6 ft of depth. Of course there are many other variables that factor in here, such as-amount of line out, speed, line dia., shape of weight. etc...

Here is a chart for reference: these are in-line style weights, but fairly close in comparison to snap weights.
http://rednekoutfitters.com/inline_trolling_weight_chart.html