I also used push to connect fittings. Cut the lines very clean at 90 degrees.
I would high recommend grounding the heated pitot and the lights using a shielded wire that runs back to your main battery ground bus. If you are using the Van's recommended GMU 22 mounting bracket make sure you use the Garmin copper screws and read the direction on other metal parts located near the GMU 22. You are trying to void any "magnetic anomaly" warnings after you install your avionics.
Factory Lycoming IO390 X, HZ CS 2 Blade,
Garmin Dual G3X 460, GTN 625, A/P 507,
GTR 200 & 20 COMM's, 245 audio, GTX 45R