Hel really are the best brake lines out there - happy to say I have been a Hel user for many years.
By using all stainless they completely moved the goal posts that the former go-to Goodridge had put up with rusty steel fittings. If you ever need a custom line, go to Hel direct, they make them up to order, whatever length and fittings you require, turn around is good too - seem to recall next day service each time I used them.
One question on your front brakes - did you clean out the sliders? and re-grease?