Hi there. Didn't catch what you are riding so some of my comments may not be relevant. I have 1100 sport and did a month tour of South Island, New Zealand last March with my wife as a pillion. It was absolutely stunning! Few tips:
1. Planning is essential. On long trips if you have back to back full on riding days you don't have time to recover. So depending on your stamina and riding style, plan your days so that you get to enjoy the journey, not only chase that next stop every day.
What worked for me as well is multi day stays in some places along the way. It gives you a buffer if something slows you down and gives you extra resting/recovery time if driving conditions are tough (rain, etc).
Carry enough water (it is amazing how quickly you dihydrate while riding) and maybe some spare fuel if necessary.
2. I found my bike very comfortable for touring. I set the suspension (Ohlins front and back) for extra load. Standard seat was fine for up to 4hr of continuous riding in my experience, although I was wearing gel padded underwear for extra comfort. I am using standard pirelli mt60s which performed admirably in varying road and weather conditions.
3. If you do your laundry along the way (and I don't see why you wouldn't) and don't plan to camp I found a 40 litre dry bag was perfectly adequate for two of us. Obviously you have to pack carefully and don't get too carried away with destination clothes. Mind you this was a late summer ride so possibly need more clothes if you expect cooler weather along the way.
These days i only use 66 litre dry bag if I need to carry camping gear as well or plan to hike. My bike has only a rear Ventura rack so I didn't have issues with exhaust heat even with rubber dry bag i was using. For bikes with rear rack only i wouldn't use anything bigger than 66 litre by the way.
Check all the rack screws periodically! Bigger load and constant vibrations over days of riding can easily get the screws loose resulting in loss of luggage and possibly an accident if you have someone driving behind you.
4. Don't know where you are going but if there is a chance that it will rain, be very ready for wet conditions. That means testing water resistance (over extended period of time) of all your gear prior to your trip.
Riding becomes unpleasant in a hurry if you get wet, especially if you know that you have another wet day in front of you tomorrow. Check creases, seams for leaks and gaps in clothing coverage (eg pants/ boots).
Boots may be waterproof but if the water is going down the pants and finding the gap to get inside the boots you are in trouble.
It takes forever for boots to dry! And tomorrow is another day of riding...
5. Obviously pack basic tools as well as tire repair kit, ties, rope, spare straps, mini rear wheel stand, chain lube, waterproof torch, maybe spare chain (maybe not if your chain is in good condition).
I was also carying satelite emergency beacon just in case I get stuck or injured outside cellphone coverage. First aid kit is also a must with basic medication.
Other gadgets are matter of personal preference but whatever you carry make sure you also have a full power bank with you at all times..
I did over 4000kms and didn't have any issues with the bike not even a minor one - it was going like a dream.
At the end i will just repeat, plan carefully - fatigue is your biggest enemy both in terms of safety and being able to truly enjoy the experience. Hope all goes well for you, all the best on your travels.
Cheers, Aleksandar