5.9 Magnum flywheel - DIY with bolt-on weight??

This is an issue for those wanting to use a 5.9 Magnum in an A-body with manual tranny. The truck size flywheel apparently will not fit. The external balancing of the Magnum differs from the LA 360 so these are not an option.

I found posts describing a Magnum flywheel being machined down and the ring gear from an LA flywheel being pressed on. Apparently the balance is not disturbed by this. I don't know what this would cost but this does not strike me as a simple attractive solution. Perhaps this was done before aftermarket suitable flywheels were available. The problem with these is cost. It would be nice to find a less expensive solution.

http://www.mopartsracing.com/parts/trans.html
$286.95 + shipping for the mopar performance unit.

http://www.mopartsracing.com/parts/trans.html
$319.95 + shipping for the Mcleod unit.

An LA 318 flywheel (neutral balance I think? - someone verify please) goes for not much over $100 and of course the junkyards would have them cheap for resurfacing. Yes I know, cast vs billet but I'm not sure that's so important unless you're going for 500 hp (other opinions on this - how much hp/rpm is a cast unit good for?)

A point of confusion came up looking at cast flywheels. LA 360 flywheels for cars are listed as 143 tooth units. This is the same as truck size (I think?) Are we certain we need smaller 130 tooth units? (Maybe the Rock Auto catalogue is wrong).

Look at the Mcleod site. It looks like the same flywheel (likely with neutal balance to start - important point that I'm not certain of) is sold for different applications, for the Magnum with a bolt-on weight.

The factory LA flywheels use drilling to provide external balance. This page shows how a neutral 318 flywheel can be converted.
http://www.moparaction.com/Tech/quest/internally.html

I suspect it would not be a big thing to add Mcleod's weight to a 318 neutral balanced flywheel. Just position it right I'm thinking, using the Mcleod unit for reference.

It's not huge dollars but hey it all adds up and a lot of folks could benefit. It is after all as much as many are paying for their entire junkyard engine! Anyway its always good to find ways to get it done for less.

I'm hoping those who know a lot more than me will give an opinion on the unkowns I listed, and the feasability of this.

link to bolt-on weights: http://mcleodracing.com/products/Counterbalance+Weight.+Steel+Flywheel.mcl