I got the movie and I am going to use it.
I am aware about the fuel tank. I have EFI engine, so I also know that the preasure from the pipes need to go out once I will unplug the proper wiring.

I will prepare myself properly.
just wondering if it is better to replace the complete tensioners instead of the shoes only.
basically i do not have the tool to remove the pins from the tensioners, but somehow I would find the way to use old springs - it is not rocket sience but the thing is that maybe it is better to have a new spring as well as the existing ones may be used already, and material "tired"

You will need to buy the proper tools to change tensioners. The new ones from Harley Davidson come with springs as a unit.
You also need proper tools to change the inner cam bearings. Incidentally this is where you should deviate from stock and use the full complement needle bearings, instead of the caged needle bearings. There are pictures on this forum of the differences. Maybe someone can repost them.
Adjustable push rods can be used also, it is more expense but does make it easier. Also I like them because you can set them to the exact length you need for your lifters. And yes with your bike I would buy new lifters.

As I already said there are many opinions here, as you can see. Even from me.

Very true.
I see already that for inner cam bearings it will not be nice and easy without the proper tool/plate.
thing is that I could machine it myself at the shop. but without proper dimensions it may be risky.
New lifters...ehh... the deeper I dig in, the more and more stuff I will discover most probably.
I have checked with the local Harley dealer - thay came with the list of components that includes chains, tensioners, bearings, sealings with the price of approx 1000 USD. as per below.
5607-99 chain

39965-99 shoe

39964-99A – tensioner

39954-99A – tensioner

25610-99 - chain

17045-99D – service kit – sealings + bearings
are the chains a must as well ?

Just changing the shoes leaves the inner link chain also. Except the Harley upgrade will now use hydraulic tensioners that put less pressure on the chain and also does not have the binding action of the backward inner tensioner.

As you can see it starts to add up. That is one reason why people upgrade to the other options. Like a better oil pump and cam plate.

Were I to do it again today, I’d be looking hard at going with a gear drive. If you’ve ever considered a cam change, this is a good time for it.

The chain drives (old and new) have quite a bit of drag. The early design has significantly more drag.

I happened to go with the cyclo shoe change myself. An interesting exercise, with some costs due to the tools necessary for it. It works, but leaves the same high drag on the inner chain.

Buy a manual.

I would just pull heads and put new gaskets in. Cost of push rods, buying bolt cutters, and no risk of ever coming loose. Just drop in.

Good time to bore 95, cam, and port.

Last year of timken can measure runout and go gear. Retro kit not bad either.

The better pads, depending how much you ride the bike.

I have decided to go by the book this time,
disassembly rocker boxes and take the push rods out.
will take some time but still.
when it comes to up-grade... it is quite costly comparing just to the tensioners exchange.

If doing the work yourself,I wouldn't think more costly. Top end gaskets are under a $100 I believe.

I don’t see any need to replace either of the chains, the chains, if anything, are smoother now and likely less abrasive on the new shoes.

The TP tensioner kit is what you want, and a gasket kit.
I replaced the inner cam bearings in mine.

I don’t know that new lifters are necessary.