A solid axle at the front gives you really good "pull out of the corners , aspecially tight corners.
But its not so good on open fast tracks. With long sweepers for instance.
You have to be used to using a solid axle at the front. You nead to set the car up to the corner, then when you get the car pointing where you want to go,.....hit the gas! .........And she'll pull you around.
I would give it more caster than 0mm. Unless you mean you have 0mm at the back of the front upper wishbone (A arm) ?
If so, then thats ok....thats what I run and its fine.
Although others I've noticed run 1 or 2mm there.
Also run 1 degree toe out at front. This seams to help.