Ummmm...OK. I have never seen a tech article that bans compression fittings. (but there just might be one somewhere) I have been building everyting from 5,000+ HP Unlimited Hydroplanes, to SCCA race cars, NASCAR, to Pikes Peak hill climb cars, to NHRA drag cars for over 30 years and never heard anything about compression fittings (there are good fittings and low quality fittings, though). As a matter of fact, I use hydraulic compression fittings on 5,000psi hydraulic fittings on Commercial aircraft. I am personally certified in "axial swedge" hydraulic fittings for both aluminum and titainium hydraulic systems. Speaking of dark ages............... . If I make a mistake 200-500+ people lose their lives. Not something I take lightly, EVER!!!! We even test our compression fittings with high pressure helium because helium molecules are smaller than compressed air (and synthetic hydraulic fluid used on aircraft-Skydrol) and is easy to detect with a meter. There are hundreds of compression fittings on the new 787 airplane. (and current fighter jets)
If you do not provide a return path for copious amount of fuel you will get pressure creep and poor pressure control. Check some of my posts on how we increased the cross sectional area of both the feed and the return path. I have even used brass compression fittings on my own car 20 years ago and they never leaked. Now I only use steel or stainless steel compression fitings which are rated for 3,000 psi. I'm SURE they will work fine with 70 psi max. If you would like more info on steel/stainless compression fittings, look into "Swagelock". Heck, the factory all now use PLASTIC fittings with EFI???