I guess it is OK this way because the senor will show "empty" before the time it would have on the donor, where the brake fluid reservoir is leaning backwards.
But my advice it to remote it because the master-cylinder is one of the lowest point of your brake circuit on the roadster, and if there is leak, the callipers/wheel cylinders will starve before your sensors show empty. The reservoir should be for that reason the highest point of the brake circuit.
That is anyway what I have done on my car:
2013-07-18_18-55-24 par
Voucht71, sur Flickr
2013-10-26_18-03-03 par
Voucht71, sur Flickr
2013-11-26_13-47-44 par
Voucht71, sur Flickr
or the full album here:
https://www.flickr.com/photos/994983...7643576951405/
I have the stencils for the Sierra reservoir brackets I've fabricated, with holes to have access to the flexible hose clamps screws. If you are interested, I can email them to you.
You will need brake fluid compatible hoses, most of the time, they are in EPDM. Don't use fuel or oil hoses.
Hope this will help