I think youre a bit confused about half lives.
The oral or injectable form of any drug is not what dictates the half of the drug. The ester dictates the half life.
Winstrol is not esterified.
I am almost certain that both oil based injectible winstrol and water based injectible winstrol (also possible to drink this) have the same 'half-life' as oral pill form winstrol.
ED-EOD dosing is recommended.
Now to answer your actual question. I have no idea how to convert winstrol pills into injectible. I dont think it makes sense to try though.