You have to remember that Lindy rigging is a finesse presentation. The walleye are finicky at times which is the reason to go to this type of presentation to start with. If they feel the slightest pressure on the line when they pick up the bait, they will just drop it and move on. Sometimes they will mouth it for a while before eating it, other times they will eat it rather quickly in a few seconds. I usually start at say 5 seconds. Feel some pressure on the line and drop it and count to 5 and sweep-set the hook. If I'm hooked up, thats good, will get it in the boat and see where the hook is set. If its barely hooked, I'll wait maybe another second or 2 next time. If its hooked a bit deep (which hopefully doesn't happen, but does from time to time), then I'll shorten the count to 3 or 4. I figure any shorter count than 3 there's no use Lindy rigging usually as they are aggressive and will bite on another presentation as well, which causes less chance for deep hooking one. Heck, I've counted to 15 before and have missed fish on hook sets, and have even had them barely lip hooked on a 20 second count. Just depends on their mood I guess. I would think the circle hooks should work too, but if you're keeping constant pressure on the line after the bite, you're not really Lindy rigging and some other presentation might work as well or better (ie bouncer and blade, or maybe no blade). But heck, why not give it a shot, who knows right! It might get stuck in their mouth before they have a chance to spit it out too, so if you're too late on the count, it just might save your bacon!