Moving my coax bulkhead entry closer to gear. Need to make some short 2' & 3' jumpers from bulkhead to coax switch/ radio to tuner/ tuner to amp, etc. I used plain old RG8X originally due to cost with the longer runs. I can afford better stuff since 25' will probably do it all for me. Something low loss, but flexible enough for the short bends.

HS

I would stick with the RG-8X.  That's what I use for jumpers to the entry panel in the window.  The longest is about 10'.  Yes, it's more loss than RG-8, but I'll accept that for the flexibility and routing convenience.

Typically 8x or LMR-240. In some cases, ultraflex LMR-400, though it's overkill for most things (I do run QRO, which LMR-240 will handle, but I like to err on the side of caution).

RG-59 from where the RG-11 enters the house to the antenna tumer, then RG-58. The total length from POE to radio is <15 feet.

Isn't rg59 75 ohm? 

You said "amp", what kind of power levels and frequency bands are you talking about?

A quality RG8X size cable works well for this application unless you're using more power than it can handle. Davis RF RG8X-LL (or the same cable branded The Wireman CQ118 at a higher cost) is what I prefer for this, the fine stranded center conductor, softer jacket material, and foam dielectric makes a very flexible, easy handling cable. The 100% shield helps with noise pickup and RF issues also.

Something else to consider is using right angle connectors, where applicable to your installation and usage.

If you're using higher power,  the similarly constructed 400 size cable from Davis RF model WM106 (or Wireman #106) is a good option, which I prefer over the Times Ultraflex types for a variety of reasons.

Yes, as is the RG11 he also mentioned. Presumably he's just letting the tuner handle the small degree of mismatch, for HF it's pretty trivial.

RG59 & RG6 types almost universally use solid center conductors, and often copper-coated steel, due to the typical use of F connectors, so they're less flexible. RG6 would actually make a quasi-reasonable coax for HF at low to moderate power levels, if you're willing to deal with the slight mismatch. What would actually be an almost ideal coaxial cable for a large percentage of amateur radio needs would be a flexible version of LMR300/RF300, which is an RG6 size low loss 50 ohm cable. An Italian manufacturer is making something almost like that but the dimensions are just slightly off from the other -300 stuff on the market, so you're probably limited to that companies' own connectors.

I have an Elecraft KPA500 & I rarely use more than 300W for CW & RTTY. Unless it's rare DX, then it's full power Scotty!

I just got home & scrounged up an 9' piece of this:  DXE 8U coax

Forgot about it down in my old go box left overs. Will make good jumper material.

RG-8X is fine for jumpers.

RG-8/U is .400" stuff.  Way too thick and stiff to bend well for jumpers.

"CQ Super 8" has worked very well for me. It handles 1,200 Watts easily. Loss is irrelevant for short jumpers on HF frequencies. Connectors can be crimped if used indoors but try to solder anything that goes outdoors, you'll thank me later.
I have also used a regular RG-8X coax with no issues.
Several jumpers were made from leftover pieces of hi-flex LMR-400 equivalent. It worked well but it's too stiff for making tight turns. I have also used jumpers bought at a "Flying J" truck stop, where they sell CB related stuff in the back of the store. It was not my first choice but I was out of town and forgot to bring my coax jumpers. It worked surprisingly well and quality seems acceptable. They sell decent mobile speakers as well as some, less than ideal, connectors/adapters and antenna mounts. It's better than nothing when you need it "yesterday".

This thick 8U is fairly flexible, not nearly as stiff as LMR400. It worked great for one 6' jumper to bulkhead from antenna switch. I'm just reusing RG8X for the rest. Your right, it would not be good for much shorter length if you need to bend it far. It's good stuff though!

LMR-240 is my preference. LMR-400/LMR-400UF as a secondary.