So im a WRT virgin.. coming with a friend that has a lot more and lightweight kit than me lol

Ive been good with my kit... and got things down to the min.... (im happy to provide a list if people want to see )

so ive got stuff packed and its all in 2x 13L alpkit bags, and one 8L one... with my Gelert x Lite mat, a sleeping bag, clothes a groundsheet,

now how to fit these to the bike ! ?

Ive got a pannier on (as bike is my touring bike) and can get one 13L bag 'on top' of that... and the other people seem to have on the handlebar (so i will have a faff and give that a go ! ) leaving me with a place to put my 3rd bag...

Do i do a balancing act and strap the two bags on top of each other on the Pannier ? or do i perhaps use a 15 / 20L commuting pannier bag i have.. and just put stuff on there ? ive never off roaded with one before so want it to be solid... any suggestions welcome ! id like to try and manage without a rucksack as we intend to stop and get food / drink so want that on my back later in the day!

Panniers can be a bit of a pain off-road, particularly on singletrack - but if you are on a touring bike then I shouldn't think that will be an issue.

Could you lash the bag under your seat? Strap / bungee around your seat post and another around the bag and through the saddle rails?

I managed with a 20ltr bag on my bars for the first WRT I did, I've still got it and haven't used it since then - I could bring that along on Saturday £5 and its yours! It'll bounce about a bit on rougher stuff but it never failed on me.

Two straps around the bag and around your bars and then a loop of bungee through those loops and around your head tube, it will rub though so protect your bars and frame if that matters to you.

Thanks Nick i dont think id get a bag bigger than the 13L alpkit one i have ? though worth a try !

My frame is quite old and i dont have much room behind me for a large bag , thus the pannier so its to plonk a bag on the top :) the rack is a lightweight one so about 600g so not to worried about having it on, when i get a new bike i will def go for the hanging method!

I'd do it this way. 13 litre under the bars, 13 litre on top of the pannier rack, 8 litre under the seat but resting on the bag on the rack. Extra straps for the seat bag could be run to the rack for further stability.

If you've got a pannier on I take it you have a rear rack? If you don't want to use the pannier then remove it and put the two 13L bags on the rear rack, either strapped side by side or on top of each other. The 8L bag could then go on your bars or strapped to your top tube if it's not too wide.
I find the most important part of carrying kit for a multiday trip is to pace yourself accordingly; if you want to cover big miles at pace carry minimal kit well packed, if you're carrying kit for comfort then ride a comfortable distance at a comfortable pace