I would never tube a block again. I don't know what kind of machinery you have available there but doing that by hand is a PITA. Worse yet is peening that tube never seems to work out well, the lifters do not move freely and with a flat tappet cam that is essential. If you really want to block the oil then bushing the lifter bores is the way to go.

Now having said that, it's a waste of money for what you have and are doing. I would block the oil to the drivers side galley though with a set screw.

Your best money would be spent on the oil pan and pickup. A 5/8 suction tube feeding the pump will do more than any other mods. You can also have the cam journals grooved to supply full time oil to the rockers.

I have a write up over on forabodiesonly.com in the small block engine section with some photos. I haven't been there in years but the thread is still a sticky.