Update on my Kevlar/ZX experiment in the Blade:
After adjusting the weighting back down to MgR/I = 21.0 and SW = 373, I took it back to the racquetball court Fri night. Forehand felt decent, but 2hb seemed to come off flatter than I like. Control was ok, but could be better.
Then I had an outdoor doubles match yesterday. In the warmups, I just couldn't get very comfortable with the Blade, and this time it was mostly due to the stringbed. I couldn't volley confidently, and groundies seemed to come off at too high a launch angle. I ended up playing my match with my Prostaff 4.7 OS instead (it was windy, and it was the first time outdoors of the season, so I felt more confident with the larger head).
I came home and noticed that the stringbed was awfully soft when I pressed into it with my thumbs -- much softer than my usual tolerance level. As much as I enjoyed the extra power on serves due to the softer stringbed, the downside of a soft stringbed (reduced control) is unacceptable for me. So my conclusion is that 49 lbs with kevlar/ZX in the blade was way too low.
Today I did something I've never done before -- I restrung my Blade using the same string (it had 4-6 hours of play already). I clamped the strung racquet on the stringer, and snipped the bottom cross and unwove it all the way to the starting knot. Then I snipped the outer mains. I didn't need to reweave the mains: I simply clamped the center mains, pulled tension to 55 lbs, then "walked off the friction slack" with my fingers several times (with the technique described previously in a stringing thread) until the dropweight stopped falling further. Then I rewove the crosses at 55 lbs. I omitted the outer mains and bottom cross (to give a 16x19), but since the outer mains ont he Blade are so close the frame, I don't think the missing strings mattered.
My hope was that this restrung stringbed would be firm and nicely playable, and also more stable, since it should already had most of the relaxation slack pulled out of it.
Hit indoors today with the firmed-up stringbed, and the results were superb. Best all-around-playing stringbed I've ever used. Definitely a little bit lower powered, but confidence on groundies and volleys was sky-high.