I have a new mare who is thin soled and requires pads up front and shod all the way around year round.  I plan on running her at rodeos. Anything else I can do to prevent soreness, like pack the feet with either Sole pack or Magic Cushion?  Has anyone made runs with packed feet? Does it help or hinder traction?

I use performance magic cushion every night at the weekend shows when stalled on concrete, I pick some out before I run but leave the collateral grooves packed and try to leave a thin layer over sole.  Never had any problems.  I also have had a lot of luck using equioxx for helping make one more comfy with thin soles/navicular issues.  The other option is durasole, it's a liquid you squirt on the sole every few days for several weeks to help grow sole and make it tougher. 

Invest in some Cloud boots, they are lifesavers.

Cloud boots are amazing! Saved my horses life a few times. Just don't use the clouds AND Magic cushion together. It will ruin them. 

My shoer is not A fan of using mAgic cushion under pads, he said it sets up like concrete after a week or two.  Between the pour in pAds or the dental impression type pads I prefer the pour in as it kind of helps adhere the pads even more so, tiny sand particals and little rocks seem to find there way in with the dental impression material where I don't see happening with the pour in material as significantly.

I still use his Old Mac boots if he is having to stand on hard rocky ground or if the warm up area available is not ideal too.

I use vettec pour in material and never have any problem with traction even on hard pan.  I don't fill the hoof to the level of the shoe.

Years ago I ran a horse using equithaine. The stuff is great. He had low heels & had to be in a wedge shoe. Worked great for him. 

I use magic cushion.  It is rubbery when mine comes out, not like cement at all........

That's interesting becAuse before I went with pads on my gelding I used the magic cushion before And after runs and I had to get the hoof pick called a Jackhammer in order to get it out.  

Maybe since mine is put on under my pad/shoe when being shod?