It's bad to open limp from the sb for multiple reasons, not really any having anything to do with the rake, AFAIK. Basically, start out opening 90% on BB and adjust accordingly. Raise 4x.

SB ranges are very player dependent.

The main points are the following:
(a) You only have one player left to act, so you have good fold equity to steal the blinds.
(b) He has position on you and gets great pot odds to call. He can also 3-bet.

These two factors go in opposite directions.

Against people who fold too much or 3-bet very tight (which is most of the people at NL2), you can open a very wide range and play conservatively postflop. Against people who call too much or 3-bet a lot, you are better off playing a bit tighter and play aggressively postflop.

Opening anywhere from 2.5x to 4x is fine.

GeoPur Play a few sessions where you open 100%, I think you will be pleasantly surprised by the results. I play anonymous so I treat every spot as unique and a one time occurrence. In a trackable environment, exploitative adjustments can be made, but try to stick to the 100% experiment and see how you do. Small blind RFI spots don't occur all that often due to the CO and BTN opening so frequently, so even if it happens 6 or 8 times vs one opponent during a session they are unlikely to catch on to what you are doing after so few occurrences.

I play in a traceable environment and I stick with the 60% open raise on the SB for most part only if I have sufficient hands I deviate from this opening more against the folders and less against he callers/3betters.

I wouldn't open more than 60-70% at micro stakes:
Rake is high, yeah if they fold so much vs raise than it is clearly profitable to raise any two (I don't think people fold so much)
Don't want to play so many spots SB/BB when they are not a lot of EV going on (many people will argue here).
I prefer tighter approach and leaving micro as fast as possible.