Just Blew 2 Head Gaskets at Once. First Run

The block was cleaned up on the decks... the heads were milled, and the gaskets are 1/2 as thick as was used at the factory... So, I have a couple questions... first, you can re-use headbolts... So long as it wasnt overheated or overtorqued for a stock or mild build factory old bolts are fine. With any fastener, the holes need to be tapped out using a bottoming tap and then blown clean to get the debris out. Each hole needs this. While I'm on the subject of bottoming out... Are you certain the bolts are not bottoming out in the holes instead of clamping to full load? Seen it before, in fact a 360 I just tore down had bolts in at 60lbs feet. Should be 95... Also, the threads get oiled with a SMALL amount of 30wt oil. A drop or two tops, or it can interfere with torque values and come out of the hole and contaminate the gasket surfaces. As far as gasket types go... If it was a MLS (Multi Layer Steel) gasket, the surface finish on the head and block must be very smooth. Smoother than most old school millers can reach. I have to tell the shop what finish i need for those gaskets. They dont just pop in like the Mr. G or Fel Pro or Victor-Reinz. Those will seal against damn near anything. MLS will not.