Thanks for the advice. I'm probably overthinking things. I'll stick with Syn Gut. Maybe later this summer I'll buy a cheap-ish poly and put that in my mains.
I string my own frames at home, so I don't need to worry about the cost of paying somebody every time I want a fresh set in one of my racquets. Since I also like to know what different string types have to offer, I sometimes sample a multifiber or a poly hybrid, just so I can do better "string talk" with anybody who wants recommendations if I restring for them.
While it will probably be an interesting experiment if you eventually try a poly in your mains, you might be getting what you need right now with syn. gut. I generally run 17 ga. syn. gut in my own racquets, but sometimes 16 ga. can be useful when it's really hot in the middle of the summer. Thinner string can really soften up for me when the mercury takes off, so I might put 16 ga. syn. gut in at least one of my rigs for some extra consistency instead of bumping the tension of my 17 ga. string too high.
Can't say I've ever tried a multifiber and been knocked out with how much spin it produced for me. There's usually some inherent softer feel with these strings, but that also seems to make them rather lively - including Head RIP Control. Unless I install multis at rather snug tension, they can soften up too much for me and that's no help with my spin or control.
The poly hybrids I've tried in recent history have seemed to deaden my string bed a bit. Volleys don't seem to have the same bite or zip with a hybrid and my serves don't seem to fly through the court quite so well. Some of this may be due to the firmer feel of the poly, but my side-by-side comparisons (same racquet model with different string setups) seem to have supported these impressions. That might help to boost control with a rather powerful racquet, but at least for me it seems to be a tricky tradeoff. I absolutely preferred the feel of thinner poly mains over fatter ones - closer to 1.20mm than 1.30mm.
A hybrid with poly mains and syn. gut crosses played a little dead and clunky feeling for me, but I've also tried the reverse layout and that seemed to make for a rather civilized setup - syn. gut mains and poly crosses. It seems as though the mains dominate the feel and performance of a string bed and this setup definitely felt more familiar for me. Plus, the poly crosses seemed to give the syn. gut mains more of a firm platform of support and a little bump in control. For a syn. gut player wanting to try a hybrid, this layout with the poly in the crosses at a few pounds lower tension than the syn. gut mains can be a decent first sampling.
Sorry for the novel, but just one more thought. I get all the spin I could want with one of my racquet models compared with the other that I also keep in my bag. Both models give me nice feel, acceptable softness, and terrific performance strung with 17 ga. syn. gut. Even when strung with a hybrid including a more "premium" shaped poly though, the changes were only mild for me. My spin factories weren't replaced by my other frames with their funky 21st century string jobs.
So I think that as long as you don't expect a miraculous transformation in how your racquet can work the ball when you try some other strings, you should have some fun trying this and that. String type and tension will help to dial in your fit with a racquet, but if you're routinely hurting for more control, spin, etc., you may need to look for a racquet that's more eager to provide that for you.
