Others opinion may differ from mine.
I would choose to keep the oil injection unless you choose to run a different oil at a ratio that is unsuitable for injection.
With pre mix, and high revs, WOT leaves very little time for the oil to come out of suspension, so I would be using a heavier oil mix
I too would be choosing an oil with a very strong film strength if I was to pre mix.
There are some guys on here who specialise in drags that have more experience than me, they may put you right.