challenging roof

I have a JLG 40 ft boom lift , that I used to build my log home . The feeling of security in the basket about 40 ft off the ground is comforting to say the least. No way would I be on a ladder or roped in with climbing gear. Rent the lift , it will be faster and way safer.

I rented a lift to do our liner, and fed the liner up from the bottom. Chimney liner depot gave me the "puller" that goes on the end of the liner. A couple good knots and maybe 10 minutes of work and the liner was up and in.

You could scaffold that roof pretty easy....you have that nice lower section for an added feeling of security...then you just run the valley, not a bad roof.....no comment on the different liner options...not my area of expertise....

I installed double wall insulated rigid by myself, and had no major issues.
I have also installed flex for others.
Personally, the rigid is much easier to install than wrestling with a long pc of flex, and a sturdier and easier to clean liner.
Rent the lift, and get it done.
I did mine from a ladder against the old chimney masonry. Same way I clean it every year.

You could also build a platform next to the chimney to stand on and work off of.

My vote is for rigid also. I used oval duraliner insulated rigid pipe for mine. Flex liner would have snagged and cocked halfway down unless you pull it with a nose cone. Solid you can push, lift, adjust and push again if it snags. I used a 36" section of flex at the bottom of mine to clear the damper section and with the oval liner it passed right through without needing any cutting or modification. Best thing about the rigid for me is you can carry 48" long sections up to the roof at a time rather than the entire thing. It rivets together and you lower it down as you go.

As a DIY'er I've now installed both, a 6" double lined rigid for my wood stove and 5" single wall flex for my oil boiler.

If it's a straight shot, I would go rigid. I found it easier to manipulate the short sections of rigid than wrestle a 25' stainless steel liner "flex" liner. It's called flex, but I can assure you it does not flex easily. With the rigid you lower one piece down, use a pop rivet gun to attach the next piece, lower that down, and repeat. It gets heavy towards the end but you can put the metal clamp/bracket on there to hold the weight while you attach the next section.

I look at roofs like that anymore, and realize I'd rather pay someone to go up there, than do it myself. Mostly because I enjoy being not paralyzed.

I have had three liners installed in different chimneys on this house, by the same sweep. I could have done two of them easily enough, by myself, but resolved to stop doing roof and chimney work when I had kids. I felt justified in this new resolution of mine, when my sweep told me he lost a lot of sleep thinking about going up on my roof for the last install.

You don't need a drill for DuraLiner rigid. It is pre drilled, just 4 pop-rivets per seam and done.
I used a pc of 14 gauge romex wire wrapped around each section installed to hold that last pc in place, while riveting the next one in place, loosen a little, lower, resnug, then install the next section. Worked great for a 1 man operation. I don't know why you don't like them, I love it, installed alot easier then the flex liners I installed. No spinning, straightening, turning etc. No 20-30 foot of flex dangling there trying to work it down.
That entire chimney must have been crooked then, cause the liner will go back straight given enough room.
Everyone has a preference, and both are good products. Just hate to see rigid given a bad rap, cause IMO it is slightly sturdier then the flex, and no outer insulation to get snagged and torn. That is my opinion, and I'm sticking to it.
Really isn't bad to do yourself either. Although either type would be be easier to install with another set of hands.

Installing my rigid liner I only needed a rivet gun and a tube of silicone to seal around the weather ring. The cap support holds the entire thing in place while you add sections. Easily a 1 man job... you might want a few extra rivets in case you drop one.. I also used a rivet stud to help align holes when it was a little shifted. You tighten the support, add a section and rivet it in place, then loosen the clamp and allow it to slide down to the next joint. To keep it from crashing down I just applied light pressure to the side of the liner to cock it in the chimney while I loosen the clamp. You cannot drill the duraliner system or you will penetrate the inner liner. Everything is predrilled for you and ready to go. Just check for bent joints on the ground before you heft them up to the roof.

I went with a double ply 16' round, 4' oval (to fit through the damper) flex liner kit with 1/2" insulation that Osburn sells with their inserts and while it really doesn't flex all that much it did help for that last couple feet through the shelf to get it to line up with the collar. Cant imagine a rigid but i guess if you have a totally straight shot it would be ok.