Process Server - Stake Out

I have about a 50% success rate with the cash for keys. For the other 50%, I often have to start a unlawful detainer action agaist the occupants of the trustee sale properties I purchase, usually they are owner occupants. What has been happening is that my attorney's process server tries to do personal service for a couple of weeks, then they request to do post and mail, then we have to tack on another 17 days I think. So we essentially spend a month getting nothing done. It can be frustrating to have to sit by and watch the occupants get away with this blatent abuse of the system by evading service.

Has anyone found it worthwhile to retain thier own process server, perhaps a private detective/process server that will research the occupants first then stake out the property at the times that thier research has shown will most likely result in a successful personal service? Starting at the expiration of the 3 day notice, if I can accomplish personal service in 3 days then the total time the occupant has to answer is 8 days. What is happening now is that it is taking at least 30 days just to get to the occupants answer deadline. I would save 3 weeks which is worth quite a bit of money, at least 1 months rent.

Is my attorney likely going to be offended if I request that at the same time thier process server is working, we also try our process server/P.I?
Is this a worthwhile expense, would it complicate the case?

I think my attorney's firm is capable but I dont know for sure if they are doing a good job or not. It seems like we get alot of delays. Any tips on finding the most aggressive and capable UD attorney would be appreciated.