If your fishing for big fish do not do the traditional knots of Tenkara, you have to do loop to loop. That will be strong enought to hold them and take them out of the water.
If you are going to fish big fish make sur that your hand that old your rod is at the good place, and that place is in the handle. If you put to much force on the section above it can break. Don't forget Tenkara rod are strong but fragile.
To make it eassier to take your line out of your Lillian, you can do a little knot at the end of it.
When you have your line still attach to your Lillian, make sure when you take your cap to do it in a straight line. Do not bend because the tip will follow it and could cause the tip to break.
When fishing in a float tube do not put to much line at the end of your rod, the reason is that you will have to much slack when bringing back the line to you and if the fish take a bite, well you will lose it for sure.
Put your rod sideway when fishing big fish whit your big rod like 8:2 or Keiryu rod