Squat Adjustment Questions

I squat low bar, but I'd like to start implementing high bar into some of the squat days or on the days where you S/B/S on the secondary squat group. What would be the best way to do this? Find my 1RM for high bar then use that or could I just take 80% of the number given?
 
Second question - I know Sheiko is based off of 1RM, but could you use a similar approach as the GZCL style where you base your cycles off of a training max (90% of 1RM) and then in the skills week (prep 3) go for REP PR's rather than 1RM PR? Or am I missing the point of the skills test where it should be a REP PR of your max not setting a new 1RM everytime?

I squat low bar, but I'd like to start implementing high bar into some of the squat days or on the days where you S/B/S on the secondary squat group. What would be the best way to do this? Find my 1RM for high bar then use that or could I just take 80% of the number given?
 
Second question - I know Sheiko is based off of 1RM, but could you use a similar approach as the GZCL style where you base your cycles off of a training max (90% of 1RM) and then in the skills week (prep 3) go for REP PR's rather than 1RM PR? Or am I missing the point of the skills test where it should be a REP PR of your max not setting a new 1RM everytime?

Boris likes to have everything as percentage of your comp. lifts. You can see that in the sheets especially in front squat. You simply figure out how roughly stronger you are in lowbar in relation to highbar and you implement it using that knowledge. I have good experience with having the second round as a variation of the comp. lift.

I am sorry, I do not know about GZCL. Care to explain?
The skill test is there to find new maxes for going forward or for finding openers for comp. In that regard it seems sub-optimal to do reps.  I hope that answers your question but I could be missing your point.

As RussianBear says that's what Mr. Sheiko recommends. I will not argue against that, but it MAY just be because thats easy to communicate.

I can say that from my personal experience, I have had great succes with choosing different exercises and training with the given percent of the max of that given exercise.
For example right now, I'm doing a Benchprogram (that all I ever do), where monday and friday I add bands to the bar (and use a 1RM that is lower, than straight weight), and if there are two bench rounds on any of those days, the second will be floorpress (using my floorpress max). On wednsdays I do the pyramid like my comp. bench.

You are welcome to check it out in my log on this site.

Anyway I'm not sure if this is 100% Sheiko-approved, but it works great for me and my workout weights feel correct.