BK diptube options

I'm adding a false bottom to my keggle and planning on upgrading my diptube to 3/4" rigid copper into a 1/2" ball valve. I had a 3/8" soft copper tube with compression fittings and very weak gravity flow...tempermental as well.
Any problems with this?

Also, what would be the best approach for the collection end of the of diptube? My options are:

1. use a cap and cut slits in the tube
2. use a cap and drill holes in the tube
3. leave tube open, set 1/2" from the keg bottom

My materials are:

3/4" rigid copper - leftover from plumbing repair
3/4" copper elbow 90
3/4" sweat-1/2" MPT connector, also copper
3/4" copper cap

Open to any/all suggestions...

Why not use 1/2" OD flex copper? In my experience, using a larger dip tube than your valve/plumbing is capable of, only leads to breaking your siphon seal prematurely when siphoning. I have 1/2" valves and use 1/2" OD stainless tube set at about 3/8" from the bottm of my kettle. I also use a fine mesh screen on the end of my tube to block hop debris. The closer you set your tube to the bottom the less you leave in the kettle after the siphon breaks.