Great idea on the bottom-up approach. I don't see how you'd ever get the washers and nuts started on the bolts in the traditional top-down orientation.
Some of these are beyond the reach of even the slenderest fingertips, and groping with pliers is an exercise in frustration (tried that first). So - double-sticky tape on a tongue depressor is your friend when it comes to getting some of these in.
Leaving these loose till they're all in is a great tip, too. That allows you to cant the assembly to one side to lock the bolts in position one by one as you fit the washers and nuts on each without dropping it back through the hole.
For the holes near the forward edge of the gear tower, I found a magnet was helpful for extending my reach.
The hardest part of this task by far is tightening the bolts. It requires stubby wrenches, box ends ground down in thickness, and holding yourself in positions that are increasingly painful after more than a few moments (at my age, at least). I managed to get a socket wrench and a box end wrench both wedged into tight crevices and stuck onto the bolt heads so tightly it took a hammer to get them unstuck after the fasteners were snugged up. A trip to the grinder for more tool-thinning prevented a repeat of this snafu.
Budget about three hours for this handful of eight bolts. If it takes you less, you have my enduring respect - and you likely have some specialty tools I wish I'd known I was going to need today.
Also, plan on naproxen and a hot bath afterwards. Which coincidentally is where I'm headed. Too much fun for one day.
Hop-Along Aerodrome (12VA)
RV-6A - N30YD - flying since '98
RV-10 - N130YD reserved - under construction
donating monthly to the VAF - thanks, Doug