The ever-popular question - what E and A goes well with guts? My current situation - a bluegrass / country / occasional slap player - no arco. Have a '38 American Standard with EP Slaps with gut. The tone, volume, and balance works well for that bass. Also have a carved roundback that only sees fair weather and indoor situations. Currently has EP Slap gut set on it as well, which hasn't been a bad way to go, but willing to take a leap if the reward is worth the investment. Love the old school gut sound - Jr. Huskey, Bob Moore, Roy Jr., Dennis Crouch. Yes, technique has about another 40 years or so to go... Otherwise, considering Oliv, Chorda, Eudoxa, etc. with Gamut heavy Lyon G and medium Pistoy D. It's a better bass than I deserve, and want to make the most of it.
I've been using all guts (chordas) on my main bass and it's great to use the gut for all four IMO. That said, my other bass is really responding well to Spirocore Mediums on the E and A paired with gut D and G. Good luck!
No arco? for the A string: Gamut pistoy, Oliv, Spirocore weich, Evah Pirazzi weich. for the E string: Any wrapped gut string, Spirocore weich, EP weich, EP slap. Having had two Eudoxas fail in the last couple of months, I can't recommend them.
I also have a '38 American standard (& a '36!). Spiro mediums over guts work better than anything else I've tried. It currently struts a Spirocore stark E and handles it well- massive power with no obvious limitations.
I'm running a Gamut copper wound A and an Animal E (or Spiro mittel) under the Red Diamond D/G. Also have tried the same Lyon heavy G and Pistoy med D on top. The RD's are the best blend. With those bottoms.