Mini tubs, advice, do's & don'ts?

I may just plasma up from the bottom right next to the frame just to make sure I get the right spot.

I'd like to keep the trunk hinges if possible?

Yeah, I'm gonna lower the car over the wheels and tires once the inside is cut free to figure out axle width.
I cut mine at the inner frame rail flange with a fiber cut off wheel ( right in the middle of the flange) taking a piece of the floor with the wheel house leaving the floor piece connected to the wheel house. Folded the outer frame rail flange over itself to gain a little more. Trimmed the difference 3/8? off of the floor piece that was still connected to the removed wheel house and lap welded the floor onto the inner frame rail flange which butted to the rest of the floor and filled the drilled plug welds from the outer flange removal and drilled new holes to plug weld the little piece of floor back onto the outer frame rail flange. Clear as mud. Right?