A few questions for the experienced icefishers amongst us

Ice fishing for me is something I do on occasion (3 - 5 times per winter typically) with very limited success. To be honest, I'm not crushed by my poor success as ice fishing is primarily just a way to get out of the house and get some fresh air during the winter - but I wouldn't mind catching more fish at the same time!

I'm fishing waters that see a fair bit of pressure in Eastern Ontario. I usually run one tip up with a minnow while jigging a Rapala Jigging Rap with a ice rod as my second.

A couple questions:

1) How many split shot should I use on my tip up? I want the split shot to stay on bottom so I can position the minnow for walleye (typically) so I often use three. Does this hinder the natural swimming motion of the minnow? Will smaller fish (e.g. perch) that happen to take the bait be able to swim off and set off the tip up?

2) How much slack do you use when setting a tip up? I use the typical HT type. I can tension the line before putting it in the hole, but then inevitably some slack appears. Big deal or no deal?

3) I usually hook minnows just under the dorsal fin. I'm looking to primarily catch & release - is this best hook rigging to avoid a deeper hook set in the fish?

4) My typical routine with the Jiggin Rap is two-three 12 inch rapid movements, let it settle, and then light shaking for a few seconds. Others have success fishing it differently?

I don't use split shot because I like some weight on my lines so I use rubber core sinkers. I just have the feeling that weighted lines will show a soft bite more reliably than split shot. I don't use tip-ups but go to the old birch or willow branch simply because we travel long distances and space is at a premium. We keep our minnows as warm as possible while in the bag/pail. They'll be far more active than letting the water they're in slush over.
I'll fish a minnow about a foot off bottom with the minnow hooked below the dorsal. That doesn't infringe on its swimming ability. Clear water, use shiners. Stained water, dace or chub. As far as hook set is concerned walleye seldom swallow a minnow, unlike slimers.

Appreciate the response - great info!