There is an app I play on that uses
5% up to 4bb for 100NL and below
5% up to 3bb for 200NL
5% up to 2bb for 400NL and above.

My question is for 400NL ($8), 600NL ($12), 1kNL ($20) should hero use a 3x RFI sizing to prevent some of the loose calls preflop? Seems like the rake would just destroy some of these calls and make both players losers. For example, if you open $15 on 3/6 for 2.5bb and BTn calls. Pot is $39 and rake is ($1.95) already. Wondering if 3bb or even 4bb opens and larger 3 bet sizes are better to avoid this rake? What is the thought process beside these environments?