Thanks for the replies.
Philippe, I did initially begin printing with drop counts closer to what you are using... and come to think of it, I didn't have this problem. That was a couple of years ago though (with a couple of years break in between) and there are some significant differences with my workflow now that could also be (partly) responsible for the different results. For example, I was using the lithium palladium per Ron Reeder's workflow, so perhaps the co-salt affects this phenomenon. I haven't tried the LiPd since starting back up as I am currently shooting for the warm tones of the sodium palladium. I was also developing in ammonium citrate and am currently using potassium oxalate. I arrived at my current drop counts because I am constantly reading that the biggest mistake that beginners make is to not use sufficient sensitizer to coat. Additionally, I have read recommendations by seasoned practitioners like Arentz, who recommends 45-60 drops (total count) for an 8x10, and Kerik who recommends .5 drops per square inch of coating area, which works out to about 50 drops for an 8x10 (coated to 9x11). Conversely, I have also read that 'plating' can occur in the areas of heaviest coating, which is kind of how I interpret the results I am getting, but this contradicts advocates of a nice heavy coating. I know what a precarious process this can be and that everyone has their own way of working, so I will continue to work towards the results that I desire by trying to synthesize the information I read with my own practice. As for your response, your volumes and my previous experience are sufficient impetus for me to go back and run some tests with smaller drop counts.
Ian, I have checked and rechecked my exposure time and am pretty confident that it is correct for my current workflow (which isn't exactly working so it's kind of a moot point =). I am exposing to a BLB array for 3:30. I suppose there is a possibility that if I have slightly thicker regions of coating at the edges of my coating area and this area exposes faster then it could be overexposing while my image exposure is right on. But with an exposure time of 3:30 I wouldn't think that it is grossly overexposing, which I believe is normally the case when solarization appears on a print. I will recalibrate exposure times when I test lower drop counts and see how that fares.
David, I normally let the paper dry down about 15 min at 70-80F and 55-65% RH. I try to expose once the paper is dry enough that is will not stick to the negative. I recently tried force drying the paper with a hair dryer (warm setting to back of paper, cool to front) and then re-humidifying the paper prior to exposure. This produced much poorer results (lower DMax, increased plating) than I was getting with my normal workflow. I am however in the process of rigging together a humidity chamber for conditioning paper as a result of inadvertently running some tests at 70% and seeing an increase in DMax and a very slight reduction in the problem described originally. I knew that humidity was important of course, but I didn't realize what a difference a 5-10% shift could make in a final print. Perhaps more experimentation in the 70-75% range, combined with adjusting my drop count, will help shed some more light on this problem.
Thanks again for all the constructive feedback,