Dr. D–If you want to try the ThinLine reins, I’m happy to send you mine to try for a bit. They are my favorite reins (small hands, gimpy left hand so it’s very hard to grip well) and I adore them. In the winter when it’s cold, they can be a bit stiff, but I do just fine with them for 9-10 months out of the year.
Wow, that’s so generous of you! 
Are you not using them at the moment? I’m thinking of stopping by Dover this week – it’s pretty close to me – and taking a feel of some of the reins they have there.
I got some Thin Lines several years ago and I absolutely hated them. Too slippy and just felt too loose/loppy. Fortunately, the tack store took them back - even after I’d used them (Tri-County - major kudos).
Thinline reins are certainly getting a lot of mixed reviews!
I have Nunn Finer ones like the Jeffries ones asterix posted but with stops (I think BoB has a non-stops version too). I LOVE them. Excellent grip and not bulky
I bought the Nunn Finers to replace the thinlines after I did Plantation in the rain and had NO grip whatsoever- it was awful. If you like the thinline ones though, I am happy to sell you my lightly used ones cheap because I never want to go around a course like Plantation again.
Have you tried these yet? https://www.bitofbritain.com/Nunn-Finer-Sure-Grip-Reins-with-Hand-Stops-p/1096.htm I have them both with and without the hand stops and absolutely love them. I’ve used them in downpours and been fine. Plus they are nice enough to use for dressage too.
I actually had reins almost identical to those when I was last competing; since breeding my mare and moving barns and trying to consolidate equipment I wasn’t going to be using for 5+ years (and/or lending it to students), they “went missing” 
I liked them a lot, though they could be a bit hard on the palms of the thinner gloves I prefer - I bought the Nunn Finer soft grip rubber reins (for cheap) and that’s all I’ve used on my “baby”, now 5 1/2.
These reins MAY turn up if I go through all my horse junk! I still prefer the reins I now have for flatwork, though (they are also fine for jumping, just the slippery when wet issue.)
My goal is to find something similar to what I now have, but with more grip when wet – my hands aren’t becoming any less arthritic as I age!
The Jeffries sound pretty close to ideal.
Take a look at these half rubber ones (very slim); https://www.ebay.com/itm/HY-HALF-RUB…75.c100623.m-1
Best choice from H&H; http://www.horseandhound.co.uk/featu…e-reins-492108
Also - unspendy.
I’ll have to hold some of these for myself – I have in the past – and see how they feel in my hands.
I think “rein preference” is very much a personal thing, and everyone has a slightly different opinion of what feels right to them 
I have been riding (and eventing) - with breaks - for 55 years, on and off, and even when I was younger I always hated the big thick rubber reins that many people love.
I never got the chance to gallop race horse, though - where those might be the best thing for the job.
I’ll pm you. But they aren’t currently in use.
Helpful thread as I am currently rein shopping. My favorite reins have always been the ones with rubber woven into the leather as linked by mythical84 (great grip in all weather, last forever, good width but not too think like rubber reins, although not particularly visually appealing for the dressage show ring). Unfortunately, I now need pony length and I can’t find any like that in the pony (48") length. For jumping, I found the PS of Sweden HVE reins (extra short 41" with super soft leather, rubber lined, and larger stops) and I love the feel of them, but I find them a couple of inches shorter than I’d like for dressage and the larger stops aren’t quite as useful when doing dressage. I currently use in full size rubber lined ones for dressage showing 'cause they look nicer with the smooth leather on the outside, but the pony size ones are only 1/2" in most cases and a bit too small for my larger hands. In addition, I find them rather stiffer/less flexible than I would like.
Based on fortraktor’s comment, I just purchased some black plaited reins (that come in pony size!) - they make me feel nostalgic (in a good way) and I love the look, so hopefully they will work well for us - thanks for the suggestion!
No one has mentioned Tekna non slip reins. Very affordable, quite thin.
When they get really wet, they are slippery with bare hands, but have plenty of grip with regular gloves.
One pair is at least 10 years old, used regularly, and shows very little wear…
When I wanted another pair, for a second horse, Saddlery Liquidators ordered them for me.
I like the Tekna reins too but find they are a bit on the short side. I use them on my shorter-necked mare and like them a lot on her. Have had them about a year now (two pairs, one each on jumping and dressage bridle), and they seem to be holding up really well. I love being able to just rinse them off, since it’s hot and humid for about 8 months of the year here.
For my big, long-necked beast, I have ended up with leather reins with stops on the everyday bridles, and plaited reins for hunting. He’s not a puller, so the stops work well for him and don’t tear up my hands, but I have plenty of grip with any of my gloves. Also, I’m in FL and store my tack in my trailer, and rubber reins only seem to last a year or two before they start melting…
These cheapiesare my favorite!! I have the Nunn Finer web reins on my dressage bridle, but they do get slippery when my horse turns into a sweaty beast.
