I found that I easily pull 200 mm stretch on my mainsail luff. I advice other homebuilders to set their system up so they can pull 250 mm on their luff before pulling block to block.

This means, roughly speaking, that the bar in the mast needs to be about 6 * 250 mm + 100 dead space bottom = 100 mm dead space top = 1700 mm op the mast. Take a little margin and go for 1800 mm. My bar is currently some 1500 mm up the mast and pretention my mainsail luff a little bit before tying the downhaul line off, just to get all the travell I need. This is doable as you always want some luff tension to get the wrinkles etc but if you have the choice than either go higher with your bar or change from 1;12 to a 1;8 system the later requires much less height. Roughly speaking => 4 * 250 mm + 100 + 100 = 1200 + margin = 1300 mm.

I found that putting the bar up the mast was actually pretty straight forward and easy. You'll need two people and a bit of communication skills + common sense to fo the trick.

I know of cascaded external alternatives that can be used on F18's and other boats but these don't allow a continious line in the 1st stage that advantage remains part of the Typhoon F16 internal cascaded system.

Regards,

Wouter