I mainly use them in 3.75 swimming them alone not as trailers and wondered if 4.25 or another length is more versatile / effective?

I don't throw rage swimmers so whatever is the equivalent to a 3.8 keitech. 

3.25s are dynamite on a finesse or downsized A-Rig

14 minutes ago, TriStateBassin106 said:

I don't throw rage swimmers so whatever is the equivalent to a 3.8 keitech. 

same here for me. I fish them bigger and smaller but the 3.8 is my go to. And if I really need it smaller you can nip the head back a little. You can’t stretch them back out. 

11 minutes ago, casts_by_fly said:

same here for me. I fish them bigger and smaller but the 3.8 is my go to. And if I really need it smaller you can nip the head back a little. You can’t stretch them back out. 

You can never go wrong in colder water with a 2inch keitech on a 1/4 to 1/8oz ballhead jig that's usually my alternative. 

39 minutes ago, TriStateBassin106 said:

You can never go wrong in colder water with a 2inch keitech on a 1/4 to 1/8oz ballhead jig that's usually my alternative. 

I don’t carry them that small. If I’m going that small it’s for crappie with a little Bobby garland and a 1/16 oz. I probably should pick up a pack to have them, but that’s just not my bag. 

I can do fine with the 3.25" & the 3.75" lengths ... If I had to choose one it would be the 3.75" version .

3.75 also

3.25” for me. I can throw it on a ned head or throw in on the back of a spinnerbait. 

3.25 is my favorite 

3.8 Swing Impact Keitech in Smallmouth Magic is my go-to, either underspin or 1/4 ball jig.

Since this post is for just the SK Rage Swimmer, heads up Dicks Sporting Goods has a 42 pack of the 3.25 and 3.75 rage swimmers for $20 but for only a limited time sale they have them buy 3 get 1 free so pretty much $15 for each 42 pack, (Around 0.35 cents a swimbait)