Lpg Installation On A Lexus Ls430

I was searching the net to check out Toroidals. I had almost decided to sell a new tank I bought recently because I had my doubts about fitting it.

Thing is, its a full toroidal with top brackets much the same as fitted here. Its only a 60 litre and size 600 x 250 which I'm pretty sure would fit OK but I think is really designed for fitting under a car. I see the brackets needed to install, and read about some panel beating to get the "larger" size to fit. That would defintely rule it out for me if necessary. What concerns me is how these top attaching brackets are screwed down at the side/base with so little room to manouvre. Measuring bracket length may be difficult

and in taking out the spare wheel Post will the tank rest properly as it has that same convex shape at the centre, below. Anyone else got a Tank like this one fitted?