Replacing 996 Fuel Lines. What Do I Need? (non-oem Ok)

Can't help with specific help, but you will need to make sure any fuel pipe you get for inside the fuel tank is suitable for being submerged in petrol & not just "normal" fuel pipe that you might use outside the tank, i.e. from the tank to the injectors. They are NOT the same.
You will be able to buy each pipe from Ducati, but I'm guessing it will be expensive & buying a suitable length & cutting it yourself will be far cheaper. Just be careful where you buy it from.

Any O-rings MUST be viton & I would consider replacing any quick release plastic fittings for metal versions. You can check out the Tom Parker web site here in the UK as they supply both the plastic versions, metal versions & spare viton O-rings.
The fittings are available in either open or shut-off versions, i.e. open - disconnected fuel will spill out, shut-off - disconnected they shut the fuel off so no leaks. This is for male & female fittings I think.
Triumph had issues with the plastic fittings they used in my 955i Daytona & the T595 versions, possibly other models too, going brittle with age. They did a recall once, but only replaced the male 90 degree fittings for metal versions, but they did not shut the fuel off when disconnected. I replaced all mine with the metal CPC ones with shut-offs from Tom Parker, much safer & better. Triumph also used odd fuel pipe sizes then too, I think it was 9mm & 11mm, but the 1/4" & 5/16" replacements worked fine without leaking.

Also, when disconnecting & re-connecting these quick release fittings a little smear of silicone grease is a very good idea to help the O-ring back into the female fitting. If you haven't got silicone grease a bit of rubber grease would do, but you only need a very tiny amount on the O-ring !

Something like this might be suitable for inside the tank, depending upon what diameter you need, https://www.ebay.co.uk/itm/GATES-SUBMERSIBLE-FUEL-HOSE-5-16X1FT-8MM-27093/183940710797?ssPageName=STRK:MEBIDX:IT&_trksid=p2060353.m1438.l2649

 

I replaced all my fuel lines earlier this year , inside and outside the tank ....
and I wish I'd found these guys before I ordered .... very good prices
.... Bosch and Sytech fuel pumps .... Dellorto carb stuff

https://www.glencoeltd.co.uk/cohlin...essure-fuel-hose-8mm-push-on-e100-compatible/

 

I have 6 Viton o rings. As568A-011 ID 7.65 1.78 wall. Standard for 5/16th quick connectors. Could always send by first class post. You may well need them if you are taking the tank on and off doing the work and silly prices from OEM. Often see them as BS-011. Instead of the American spec. These are shore hardness 90, medium hardness range. 70 shore tend to be just too soft if you are taking on off regular. Never used anything except tiny amount of soap for fitting o rings. Doesn't help but you have lovely clean hands.

 

A fire extinguisher, a bucket of sand and an assistant, just in case it goes Pete Tong.

Ask me how I know......

I had the tank on my S4R (996 engine) wrapped during the summer and the dimwit who refitted the tank afterwards spilt one of the fuel lines. They obviously never tested it, so the first time I switched it on after it was delivered back to me in a van it sprayed petrol all over me, my son, the battery, the jump start booster pack and front exhaust header. We were very lucky not to have been incinerated.

I also had an leakage issue with my S4 special which has a 916 tank fitted. You'll probably end up using non-OE quick release connectors and IME, they don't fit quite as well as the Ducati items, meaning that sometimes they don't click home fully or the o rings can get pinched. Either of these issues, again, will lead to petrol being sprayed everywhere (specifically the headers and battery) the first time you switch it on.

 

i've been trying to find the correct link to some aftermarket quick-release couplings that many of us have used, in case you run into trouble with the O.E.M. ones. The originals are usually ok with patience though.

These are very similar but the tank coupling needs confirming with supplier:-

http://www.emotouk.com/mvagusta/fuelfittings.htm

 

O rings of 75 or less hardness are more likely to pinch. They are just too soft. Ask when ordering Viton O rings. If they do not know the Shore hardness do not buy from the supplier. It is important. Splitting a hose takes some doing, tough stuff probably tugging on the hose to open the connector not really knowing how they worked. The only idiot I let near my fuel system is me and I did turn a Triumph Tiger 955i into a torch! Did not replace the existing o ring after taking tank off.
Lucky escape for both of you,hope no one was hurt. Rule of thumb, have spares and replace o rings every time the connectors have been opened. Buy from a supplier who can give batch number and date of manufacture and does not think Shore hardness is a measure of beach impact. You can buy 10 for £5 delivered from a good supplier, cheaper by the dozen. Throw them away if more than 3 years old.

 

All fuel lines are subject to batch testing. Always ask for spec sheet. Simply fitting them to a vehicle or vehicles and saying how well they work is meaningless on pressurised fuel systems. Material used, pressure testing spec and actual results, dimensional tolerances. Lots of crap being knocked out at bargain prices, all nice and shiny. No certs, no buy.