Don't do it! I don't think that trying to rebalance a manual trans flywheel is a good idea at all. Try to find an aftermarket flywheel for your application , OR, relace the crank and balancer with it to ensure the correct balancing
I just sold one on ebay for 90 bucks, the guy that bought it thought it was for a 5.0. If you want, I could
contact him and see if he wants to sell it (289 28oz flywheel). Email me if your interested..