Not sure if this will get answered, but I have been playing with a new front end for my trike.
Not a big springer fan, but it was what I started building months ago, now not building a true springer design.
I am in favor of the Hyd. shocks up front like the leading link design, but do not like the wrap around design either. I do understand the stabilization that occurs with the wrap around, but I see it as needed when the rocker arm (leading link arm) is to long and more strength is needed to keep all straight.
I have a 48 degree rake on the neck tube with a 2 1/4" offset Triple Trees, Harley 39mm set.
I do not see mounting the lower end of the shock near the axle point a benefit for me, it will just increase how much the shock is laying horizontal, and at some point it this angle effects how well the shock works, remember hyd. tube shocks stop working after 40 to 45 degree angles are met.
Kind a stuck, have had the rockers already cut out, but if I am right I should have room to move more forward towards the axle if truly needed, but I just do not see why I should.
My mind says that I should just lay the shock at the same angle as the main fork tube is, keep the shock mounted parallel to the fork tube.
Again as mentioned before, as you change the angle a shock was designed for, well you lesson the coil spring strength...….still trying to find where I read it and how to figure out how this will effect the design and the shock that is needed.
Looking over it all again chasing that magical shock I discovered that I was looking for a 6" travel in the shock, but I do not need such travel. The lower shock mount hole is 2 5/16 " forward of the RPP, and is 3/4" lower than the RPP line to axle point. This is needed when the rocker is set 90 degrees from the fork tube. When all is set up and you rotate the rocker through it's travel range the lower shock mount hole only moves 2.75" of travel while the axle point moved a total of 6" of travel.
Still searching out the data charts for the shock that meets my front ends needs.
Weighing the front end when the trike is totally together is most ideal for trike owners. I say this because as I added weight to the trike's naked frame I found that at different location this weight is added I got a different ratio of how much of the weight was felt at the front end. I do not think there is a general rule or ratio that should be used on trikes, each seems to be a little different and should be treated individually.
Just my thoughts about it. So how much spring does a coil spring use when mounted at 48 degrees?