18x20 is my preferred pattern and whilst I haven’t used the spider rebel I have hit the banana reb and used the Rad Tour Zebra which also has similar specs. Generally I found that in a softer heavy players frame with a dense 18x20 I preferred a very thin gauge soft polyester at low tensions 48-52. Just helps out with more spin. There are several choices out there to suit most budgets. Cyclone springs to mind although currently I’m honeymooning with Hyper G in a Tour 100P which has everything I need from a polyester. Both are available in 1.20 although I think that Hyper G goes down to 1.15.
I'd pretty much echo the others. Usually a softer full poly at a lowish tension or a hybrid with the poly in the mains. 45-54 lbs. depending on the particular string.
My favorite of all time was Lux Ace in the mains and Rip Control in the crosses at 50ish lbs. Awesome in every way except durability. If money were no object I'd probably have 6-8 frames with that string in it. It was like magic for 30-45 minutes.
Only thing that has ever come close for me to that was Alpha Gut 18 around 55 lbs. Amazing feel. That string could possibly break after 6-8 hard first serves though. So it's pretty much not an option even if I was rich.
I was playing this setup with pro blend in the 60s then 55lb (played it in the 90s and never changed). Which felt like a board and hitting a rock. Recently trying lower tensions but I've gone too low at 30lbs and moving up. I do like the lower tensions for my arm, sweetspot, power, depth.
Stringing 18x20 with poly on a 95 sq is no fun at all, too many strings, too little space. It also feels very wasteful to string it once, cut it out and try different strings and tension so I'm trying to get a better baseline of the tension and string so I don't waste time and strings. The good about kevlar at 18x20 is one of my rackets can last a year.
The latest poly's really work with 18x20. Find a good set up and you'll have a racquet which is great at everything. I'm using firestorm 18g in my six one 95 @ 48lbs. Very soft & powerful but with control and decent spin.
I have been using that racquet for a number of years. I tried Luxilon 4G at 45# recently to try to get more spin but the next day I had a lot of arm pain. I don't think polys work well with this racquet. The string pattern is too dense. I am still looking but I have had the best luck with plain old Prince synthetic gut at 55-60#. Multi filaments are too powerful without adequate spin. I hit with a lot of power and expect the ball to at least dip a little but it is difficult to get adequate spin with this racquet. It is a flexible but powerful rock solid racquet without a lot of spin. I just don't think strings are going to make much difference.
The Rebel 95 is a soft, very flexible frame with cushioned feel. Though I have the Gut mains with poly crosses right now, this racket can be strung with full-poly around 50’ish pounds and still feel really nice. I do like the O-ports, especially on a 95 headsize.