Flat Top Slide Winter Project ?

[Slapshot]

I've got a Norinco 1911, a vertical mill, and about 6 months of Winter to get thru. I've been gathering some parts and doing some research and I have a question. I know most slides are tapered so what do you locate off of when flat topping a slide? Do you indicate the top of the slide or the rails? Any input would be appreciated.

 

[Cloudsmoker]

Not a pro, but I indicate off the top of the slide. Take small cuts and double check that the width is equal from front to rear. I generally shoot for about .35" width and hope that the cut lines look parallel at about that width. If it's mostly about looks, make it look good to you.