Keggle Ball valve placement?

I would like to apologize in advance if these questions are alreasy answered in another thread, I could not seem to find them through a search.
I recently picked up three kegs and had a local machine shop cut the tops out for me. After searching the forums, I have to decided to go with welded SS 1/2 fittings for my valve and thermo. I will be using the Bazooka T-screen. Are there any specifics with the placement of the fittings in regards to the bottom of the keg?
1) How far from the bottom of the keg should i drill the holes for these two fittings?
2) Do I drill a 1/2" hole or does the hole have to be a little bigger for expansion during the welding?
3) Is the T-screen durable enough to be used alone as a false bottom?
Any help would be appreciated.

Thanks!

Drill the holes close to the bottom but above the curved section of the keg. You want the fittings to mount perpendicular to the keg. Each of my keggles have a 3/8" pick-up tube that runs to the center of the keg and then curves down to bottom. My HLT additionally has a length of s.s.braided hose attached to the end of the pick-up and It works without a false bottom. The draw back to not having the false bottom is that I can not heat the mash with it's burner. As far as the hole size, I would get the recommendation from your welder.
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Mark,
Thanks for the info. This might seem like a goofy question(<--read:noob), But why can't i heat my MLT with only a bazooka screen? If that's the case, I will just go with a false bottom.

The ideal behind a false bottom is that the grain bed is elevated a couple of inches above the bottom of the kettle. This leave a reservoir of liquid that can be directly heated and circulated back over the grain to raise the mash temp. If you just have the braided hose filter the grain rests on the kettle bottom to possibly scorch when heat is applied.
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