A lot of your design is going to be affected/restricted by the car around it. That being said, I think its hard to give advice regarding geometry without seeing the rest of the chassis.
I only guess you are building a Formula SAE car, so in that case low COG is your friend. You'll also have to take into consideration things like the dampers/springs/materials/wheel offset/ that are going to be used.
Long control arms need to be backed by stronger dampers/springs/antisway bars to negate the extra leverage, unless you change the pull rod ratios (amongst other things). The opposite goes for a short armed suspension.
High/low offset wheels can also change the leverage, so choose accordingly.
If you are able to post pictures, it would go a long way towards providing a valid opinion of your situation
Best of luck on your project, I'm interested to see what you come up with!