Adding a slope to seat sliders -- anyone done this?

I share a track car with my girlfriend. It's a 2017 BRZ. She put the cage in it originally and it fits fine for her. I drive it more than her lately, just due to different priorities. 

Issue is that I'm 6" taller than her and my head will contact the cage bar above the door when I'm wearing a helmet. However, if I lower the seat more to give clearance, then she won't be able to see above the wheel. Given that it's her actual car, it definitely needs to remain drivable for her. 

In asking around, I found that some folks have had success with putting the seat sliders (also necessary due to height difference), on a slight slope. This way, when the seat is pushed back, it also goes down and vice versa. 

I am pretty green with fabrication of any sort and am trying to wrap my head around the best way to make something like this. It seems like simple washers or blocks wouldn't work well, as they'd have too much of a hard edge and create a place where the slider could bend/break. Seems like some sort of angled block would be necessary, but I'm not quite sure how to create that. 

It does seem like a little would go a long way here, so maybe I'm overthinking it. 

Anyone done this before and have any advice to share?

I would buy something like this: https://www.ascfabrics.com/product-page/seatrisers and see if it actually solves your problem.  I tried a similar product on a BMW a while back and found that my total headroom decreased.

If they work, take the sliders and spacers to a fab shop to build a safe version.  I wouldn't use these long term because most designs stress the seat bolt in the wrong direction.

Yes, I've done it on several racecars.  It works.

It is gonna be vehicle specific on how the slope is achieved.  

Some of the vehicles, I was able to raise the front with some fabricated blocks.  Other cars, it was necessary to only lower the rear.  Finally, on my 2nd gen rx7, it was necessary to make a drop seat pan that included the angle in the drop pan.

That last way is pretty intrusive for a vehicle.  Only do that if absolutely necessary.

Check to see if Desert Does It has front risers that will work for this car. Even if they don't list that application, ask if they have something off the shelf that might work. I've bought three or four sets from them for Toyotas and Hondas.  Great product, and they are easy to work with. 

Yes, I have mounted sliders on a slope so that that the seat is higher the closer it is to the wheel.  However, in a dedicated track car with known drivers my preference is to use seat inserts.

I run the seat sliders on my lemons car at a pretty steep angle. This really helps the taller drivers pass a broom stick test while letting me and the other shorties see over the steering wheel. Only major downside I've had is it's a b!t€h to slide the seat forward as it really wants to go with gravity.