I have read this somewhere on the forum before, but I cannot find it.  

I have two AMD-65 kits, which I will be assembling with OOW receivers.  I do not wish to drill-out the rivets in the trunnions, if possible.  I want to file them flush with the trunnions, place receiver over them, and match drill for button head machine screws.

Questions:
1.  What size button head machine scews do I use for both front and rear trunnion?
2.  What locations are best for drilling?
3.  What measurement should I drill?

Any advise or photos showing this is greatly appreciated.  

Maybe some more info would help.

You are going to create brand new holes for the screws, correct?

Any particular reason why?

Yes, I plan to create brand new holes for the screws.  I plan on leaving the rivets in the trunnions (filed flush) for two reasons: 1. less work; and 2. news holes drilled through the reciever and trunnion will match.  I believe that OOW recievers do not have trunnion holes already drilled.

I prefer to have my recievers TIG welded to the trunnions, but I have not read much supporting this process.  My TIG welds would be more than 4 rosette welds per trunnion; I would weld them wherever I could find a seam of reciever and trunnion.  The G-3 and CETME are stamp metal recievers and welded; I think that other H&K rifles are welded as well.  These rifles seem to hold up well enough with welds.

I drilled new holes like what you are talking about on my last build but I snapped off a tap in the front trunnion so I had to drill another hole leaving an open hole on the receiver, Man was I Pissed!. I patched it all up and looks good but If it were a screw build I would drill into trunion, tap and make sure everything is good before drilling the receiver. If it were a rivet build I would drill the receiver and trunion at the same time.

if u tig weld it it would b stronger then those rivets ive seen a few dont that way
just weld front and rear leaving room for your forarm in front
then drill few holes threw side of rec into block and weld those also
file it smoth and it looks like u have a milled ak

I tried to do what you are descrbing using an underfolder trunion...  Just think three times over before you drill as it is easy to forget things like where your selector goes

If I were to trywhat you are suggesting, I would get everything mounted up asnd drill a tiny locator hole through the receiver and into the trunion then drill and tap the trunion and come back and finish the hole in the receiver...  

As for the screws 10-32 are the correct size...

As for location, I used Avery labels to allow me to get an exact indication where my rivets were and stuck the label to the side of my receiver.  I guess it would work for your goal as well not that I would do one as you describe...