TheEnforcer81

What works fine for me is keeping ALT pressed while attaching parts to nodes - this makes them stick only to nodes (facing the appropriate direction as somewhat pre-selected by the part's rotation) and nothing else. Might be worth a try - if I'm not currently telling you old boring stuff you already knew

Just a shot, but mind you that - unless you carry extra LF for the engines which don't require LFO - these engines draw their LF from the LFO tanks, leaving you with a surplus amount of Oxidizer, which is totally useless since it's not gonna oxydize anything at all - but might be displayed as available fuel / deltaV. I've been running OPT 1.8 on KSP 1.05 and never (a. f. a. i. k) experienced any crossfeed issues to be honest.