How about this?
12" heavy (185, 225, 275) 3x3
10" medium weight and volume, (135, 185, 225) 3x5
8" light weight, high reps (135, 155, 185) 5x5 and then back to the
10" medium weight low volume (135, 185, 225 for 3x3); maybe this is actually where I'd start, next DL day.
And then each time through the cycle add weight or lower all the heights by 2"? That way it will be 4 months before I'm actually pulling from the floor!
In all honesty, I reckon you're over complicating things. Now, that's probably contradiction of the year coming from me! I'm deffinitly the guy that fails to see the forest for all the trees, ya know.
You're right about changing every 2 weeks. Every 4 weeks will be better.
Think of rack pulls just as 'a deadlift variation'. So, on that specific day, you do a deadlift variation. This could be rack pulls from above knees, below knees, speed pulls, sumo's from mid shin - anything, whatever you've decided it will be. If you're lowering the height - just approach it like a new exercise. I wouldn't purposely lower intensity - due to 'playing around' with a new variation, the intensity will be somewhat lower anyway. As long as that variation is within the limits of you're flexibility, then the actual variation you're doing is negligible - as long as you're rotating every 4 weeks or so.
In terms of rep range - Just vary depending on what you've been doing. If you do low reps for a while, you'll be bad at high reps, and vice versa. When I do a new variation I like to do slightly higher reps, then I take it down on the second week and go all out, for example. So, in you're case, you may want to do sets of 5 for the first 2 weeks, then sets of 3 for the next 2 weeks...
For variations what would you suggest? Sumo, suitcase?
The only thing you're limited in is depth. You can still do conventional, Sumo, and snatch grip. And you can vary height on all of these. As long as you don't go beyond the limits of you're flexibility, then the deadlifting world is you're oyster! With regards to suitcase DL's - In terms of program design, regard these as a 'core' exercise. You might swap Pallof presses for these, for example.
Sometimes one of the best things you can do is pick a really horrible variation. Sometimes, I'll be doing a variation that allows me to pull 450lbs+ and sometimes i'll be doing a variation that all I can pull is 330lbs. Sometimes i'll do close stance, low box front squats, or squats from pins, and I use ~230lbs - and i'm not talking about speed work here! And when I go back to the variations that i'm training for, almost all of the time i'm stronger.
Also, the horroble variations that are REALLY difficult, awkward, and require hardly any weight also give you're spine a great deload. You can deload it for a whole month and still get stronger over all - now that's productive!
A note on snatch grip - Straps will probably be needed, at least when you get comfortable and heavy. Also, when you go snatch grip, you're essentially increasing ROM just by making you're grip wider. This just needs to be kept in mind... Most will dread the thought of snatch grips, but you may just fall in love with them - one of my favourites (snatch grip rack pulls)
To speed this up the best you can do is stretch what's tight. I'm guessing hip flexors?? It may be worth while trying to put together some stretches or mobilisations for muscles/movments that are restricted - something that will take 5-10 minutes and you could do every day. This done a long a side a program that works 'around' your issues (which you already have) will see results as quickly as possible.
I know what you're thinking - "KPj has a friggin cheek telling ME i overcomplicate things".... I don't know what happens - start typing/thinking and can't stop!