Hi All: I really enjoy playing around with open tunings and different guitars seem to lend themselves to different tunings. Here's a family portrait of my collection: from left to right a. The 9220 Bobtail resonator with a plywood body & spider cone resonator b. The 9221 Bobtail with a steel body & spider cone resonator c. the 9202 Honey DIpper with a brass body & biscuit cone resonator All of these resonators are plenty loud even without amplification. The plywood resonator las a lovely clear tone- very "dobro-y" and I have in a standard tuning, strung with the manufacturer's recommended D'Addario phosphor bronze light .012-.053 strings. The steel bodied resonator has a beautiful, pure, clean, metallic tone that lends itself to the open G tuning and the songs that appreciate the sweetness that that tuning can express. I also have it strung with D'Addario lights. The Honey DIpper is perhaps my favorite of the bunch. The brass body gives this guitar a voice that is resonant and rich with many undertones that make it somewhat muddy to me ears when tuned to a standard tuning, but it really comes into it's own in an open E or E minor, and it does things no other guitar I've got can accomplish. I have it strung with D'Addario mediums (.013-.056) as per manufacturer's suggestions. I want to mess around with some other open tunings, especially the open C tunings that call for the low E to be dropped to C, but when I retune any of my guitars in this way the C string almost feels slack and I get crappy intonation. The solution to the problem is probably to change strings to a much heavier gauge so that the strings will be taunt even though their tuned so low. My questions for anyone with experience in these issues are as follows: 1. If I just change the lowest string but leave the rest as is, will that put any undue stress on the neck? 2. If I change all of the strings so that the guitar is strung with heavier strings that the manufacturer recommends, will that be detrimental over the long run. 3. Any recommendations for strings for open tunings?