Some updates here.
Through multiple trial and errors I was able to reduce UMTS signal drop by at least 50% by performing the following changes, though reception is still a lot worse than GSM native phones.
1. In my build.prop I made this line effective by removing the # sign:
2. In our /system/lib/ we do not have this file, so I got one from an Asian baseband (Singapore) of the XT720, from this thread and copied it over, do not forget to set permission 644
3. I suppose replacing the right "libmoto_ril.so" is the key to eliminating signal drops, but replacing the ones from GSM Razr and Droid 3 got me reception bars but I was no longer able to make phone calls, so I had to use our stock "libmoto_ril.so" for now. Do share your collection of these two files if you don't mind.
4. In my latest attempt, on .905, I was able to apply the GSM patch, and thanks to linyincsz, by adding this line "telephony.lteOnCdmaDevice=0" to my build.prop and a subsequent factory reset, I am now on the latest Gummy nightly with bad but usable bluetooth.