What is your preferred formula for a hand made leader for throwing clousers to sandbass and small striper on a 5/6 wt ?
There is definitely not a perfect formula for this! Experimentation is the beauty of it. I'll try and give you what I might try first. If we are talking about the creek sand bass spawning runs you are likely looking at fish between 5 and 15 feet down and likely will want a nice uniform sink. However, again that might not be where they are For instance last weekend They were almost on the surface and no depth was required, but I digress.
For the spring spawn run my go to is 5wt Sink Tip line matched with a sparsely tied white or white/chart clouser. 2nd Favorite is a mylar minnow.
I'm likely to tie up a 3 part 9 foot leader of 100% Fluoro starting with 5' of 30 lb down to 2' of 15lb and finishing with 2' at 8lb. 60% butt/20% mid /20% tippet is usually a good starting point, but again you can experiment. If anything I like to heavier on the butt section to get plenty of help turning the fly over. With just a few sessions you will get extremely good at gauging how much to pull off the spool to allow for the amount the knot and tags you clip. I did start with a yard stick with a binder clip screwed to one end and a screw in the other to wrap the other end for sections longer than 36". However, after 3 or 4 sessions, this is now collecting dust.
As far as varying that, I might tie a longer one up to about 12' total to get more depth, I might tie a lighter tippet section if the water is extremely clear (leaders are usually not a problem for sandies and the occasional striper can often be found with them that time of year). I might tie a heavier and/or longer butt section if I'm in tight quarters surrounded by brush and need to do a lot of roll casting.
Another variation would be to switch the tippet section to mono. It's a little tough to describe, but that will totally change the action of the fly on the retrieve as it will not sink as fast as the fly. It will add additional vertical movement, perhaps mimicking a previously wounded bait fish.
I'll leave knots to others as there is no end to that debate......LOL
Anyhow, I hope what came through is that there is no perfect formula, but once you start to understand how important the leader is and how changes to it affect things, it becomes just another tool in the tool kit.