The two ton coil you rigged in to the hpwh is plenty large enough...but for a water grabber. You seem to have indicated it was doing a good job in that regard without overcooling the house. The thing you want to deal with is the high pressure side.
I still like the idea of the desiccant waterfall. A number of members have been interested in them but I haven't seen the results of anything yet from individuals. The basic idea is this: you pump a working fluid (salt water) between a water grabber indoors and a warmed evaporation unit outside. At lower temperature, the salt naturally wants to be a weak solution, at warmer temperature it naturally wants to be a stronger solution. I did a proof of concept experimental rig using calcium chloride ice melting salt, and found it works pretty darned well. I commented about it in another thread here. That method would use a whole lot less energy than a refrigeration cycle would to get the water vapor outdoors.
This liquid desiccant idea could work in tandem with your hpwh / dehumidifying rig you have going now. If the interior RH is too high and your water is hot enough, you could use the waste heat generated to heat your outdoor water shedder. This is known as "double effect" as you are reusing a waste product in the process to further the process. It is a proven way to gain another 30% or more efficiency from your system. Used all the time in industrial processes with waste heat products.
EDIT: Found the thread. Be my guest.
http://ecorenovator.org/forum/solar-...umidifier.html
The interesting begins about page 3 or 4. Leads to a discussion on the Coolerado and DEVAP units. Read that one too.