Alex, its great to see you're back on this kit. The work you've done on opening those doors is truly amazing. It reminds me very much of your '64 Ferrari 250 GTO. That model is inspirational.
With regards to the fit of the MFH kit, I think its only fair to say that more recent MFH kits are of a higher standard. I have a few of their 1/12 kits and I'm really impressed. I wonder how long ago they originally made the 512BB/LM kit? I was tempted by their 250 Lusso (also in 1/24 scale), but I'm wondering if it will also suffer similar fit issues.
I really do hope you do press on with this. The work you have done so far is too good to shelve again. If you do continue, I will be watching avidly.