Thanks Jack, what racket and tension do you string your hybrids at ?
Am used to playing with full multis at around 60lb. I am trying to get a similar experience with hybrids with increased durability.
What tension would you recommend for SPPP/Natural gut to play close to 60lb full multi job ?
I use the Prince Warrior OS, and I string both the mains and the crosses at 67 lbs. I understand that this is pretty tight, but this is a 107 square inch frame with a 16x19 pattern, and I hit fairly hard with a lot of topspin. Therefore, higher tensions give me the crisp response and control that I like, particularly with this pattern. (I should also mention that I've weighted this frame down with lead at the 3 and 9 positions, so it plays more head heavy than a normal Warrior. This is supposed to be harder on strings, but for some reason, this racquet does not saw them up like I've experienced with other racquets.)
Natural gut retains tension very well (probably the best of all strings) and is very resilient, so I would string it at 60 lbs if that is what you like. The SPPP retains tension well for a poly, but due to it's relative stiffness compared to a multi, you might want to drop the tension 2-5 lbs.
As to your question about the durability of gut, yes... natural gut will outlast and be more durable than a similar gauge multifiliment or synthetic gut. It will also retain it's playability much longer... pretty much until it completely frays and finally snaps. However, in my experience (as I mentioned previously), when used as a cross, the natural gut outlasted the 17g co-polys I've tried. Maybe I've just gotten lucky with the Tonic. However, I've also used Prince TopSpin and Technifibre X-1 Biphase for crosses with poly in the mains, and in those cases, the crosses always broke first.
Several others have mentioned using Gosen in the crosses. While I have not used this myself, I would be remiss not to mention that two of my friends use this for their cross strings in a hybrid, and they love it. Both of those guys never spend more than $10 for a set of string, but they claim that the Gosen is just as good or better than any other synthetic or multi for a cross. (However, I'm not sure what they are comparing it to because they're both too cheap to try natural gut or a high end multi... to each his own. Play what works best for you!)