When would substantial holder show up ?

I know i said i would not talk about shorting again but a question as shorts on pet approaches 2%.

If i wanted to gain a substantial position but wanted to remain under the radar, would loaning my 4% to a shorter then buying another 5% as the stock fell be a possible tactic ? Do i need to notify of substantial holding before the loaned stock is returned ? Of course if i didn’t then approaching it this way would keep any possible competing instos unaware of my building position.