IMO, no need to drill #1 main as it is fed right off the pumps main feed vs the others that get fed off the upper lifter gally.
I like the idea of drilling between the lifter bores. One it helps get rid of extra oil there and two it directly drips oil on the cams lobes.
The negative would be the extra oil dropping into the reciprocating mass.
But, I believe that is a misconception in a race car. I feel that during acceleration most of the oil is thrown and drained down at the back of the motor. IMO, it only drains extra oil around the lifter bores , if the holes were drilled as you described at idle and cruise. Witch would help lubricate the cams lobes better in that enviroment. My block is currently drilled like that.