Try this for balancing:
http://www.borlainduction.com/media/..._throttles.pdf
Regarding mesh/filters, the tea-strainer type gauze is hugely restrictive. I use individual tall K&N filters each completely covering each trumpet for road use, which is only slightly restrictive at higher RPM. I have reasonably high bonnet clearance which allows that. On track I have the trumpets open so they're completely unrestricted; the difference is noticeable.