[Steelerman]

Typically you want to look for an SPR between 2 and 8 for TPTK or overpair-type hands. In PNL, the authors say that when you don't know your opponents, you might use a target SPR of 4 for TPTK hands like AK & AQ.

Obviously you would adjust these numbers up or down if you had reads. Against a super tighty you might look for an SPR of 2...against a donk who will overcommit with TP weak kicker, you could push the upper range towards 8.

Also, remember that you have to adjust your target SPR's down in multi-way pots. While you might stack be willing to commit with TPTK heads-up you wouldn't feel so good about it in a 3 or 4 way pot.