I know with the 1/8 off-road the cure to this problem with pin tyres is to at first cut an outer row of pins off and test, you can cut more off too until they perform as you like.
Adjusting roll centers may help too, raising the camber link on the inner location up will lower the roll center. That did help me so it could be worth a try, remember if you are setting up try and do just one adjustment at a time.
But in the whole scheme of things Chris is right, you aren't running on a track, there's no set course and you are "free to roam", rolling any car is probably easy to do in this environment.
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