Gregg - I think you're better off with a pro doing this for the aforementioned reasons. It's just not worth the trouble.
Jim - Can you advise Gregg (and 'others') 1) should he be sure the contractor orders a hydraulic-type cement (or not), and 2) what PSI is usually used? I ask this from the perspective that he, Gregg, gets this type of info written onto his estimate. Thanks in advance.