This is a little off your present discussion, but as we know, we have talked about this privately.
I eventually converted my LD to SL series, and it works great. I prefer the round foils to the aerofoil shape of Harken
, etc, so wanted to keep them.
The change I did make was to support the torque tube assembly up off the black, centering do-nut with 2, 1" x 1/8" stainless flat bars, ala ProFurl, with a longer pin thru the stem toggle. These bolt thru the 3"+ diameter tube below the drum.
With this arrangement the donut carries no weight, and snugs the whole assembly neatly.
I experimented with a made up plywood
drum, bolted to the LD drum before making the conversion to SL.
It works quite well, you might try that as your first step to SL.