I will take some pictures in the next day of my boxed mounted... The Power factor/RRP box has 4 tabs you can bolt to the firewall.. I have also seen it strapped in the front of a ski...
My LPW ski I ran the msd on a plate with the solenoid , etc.... I had the coils mounted on a plate that sat on top of the battery... For a while I ran Kawi oem coils (I think off a 3 cylinder kawi) then switched back to msd coils...
Big thing I found with open msd and saltwater.... The complete motor , coils, and msd needs to be sprayed with silicone type spray before and after every ride... This really helped, other wise the salt would cause the coils to arch and drop a cylinder...
2nd all connections need to be water tight, marine heat shrink connectors, then heat shrink over all connections.. I normally double my heat shrink...
Also I don't cut my start / stop switch and hard wire.... Take the harness off a oem box and hard wire that so your start / stop has factory plugs...
Use dielectrical grease on all the connectors / plugs
Grounds.... Very important.... I prefer to have everything on one plate, coils, solenoid, msd unit, etc.... I make a ground stud ( counter sink on the rear of the plate, install bolt, use lock nut to make a stud) I then run a ground wire from both bolts on the coils to Grd, 2nd ground the msd, 3rd ground the starter solenoid.. I use common wire for this... Then I run a 6 ga ground wire from the stud direct to the starter bolt, along with the Grd going to the battery like a normal ski...
having good grounds helps keep everything working.... I have seen TL setup with just a small ground wire going to a bolt on the intake... It worked okay but needed attention at times...
As for the starter solenoid.... I have tried a/m ones, sea doo ones.... Best luck I have had is with the late oem Yamaha style .. I got the last 2 from Brian at Thrust
As for the JSS MSD TL wiring.... I haven't seen one in person, it appears nice from the photos I have seen... Like I said above I like using factory plugs.. I'm not a fan of having extra bullet style plugs and there seems to be a lot on the jss built tl setup......Less connections for water to cause problems with the better.... Not talking bad about John at JSS, this is just my opinion ....
Running MSD in fresh water you don't see anywhere near the problems as saltwater... Saltwater and MSD are not friends... Also MSD and salt water will give you a nice shock....FYI
This is just how I run mine.... I'm sure there's better ways to do it, but this has been proven to work in all conditions...