Piano finish... mmm... sounds bloody lovely. I am just sticking with Duratex for now and the first bit went on last night (in the mouth of the horn) and it looks niiiice.
Once I get this one done I can start building me some Otops
Waiting for castors though. Putting them on the rear of the speaker (if the mouth is the front), so it will roll around with the mouth facing up and then castors removed once in situ. I'll be using these ones:

as the Penn Elcom "non-rattle" castors 2060 (pictured below left) rattle like hell!


These ones on the right don't though (0147)- really smooth wheel rotation with no play, but it means rounding off a 30mm corner, which means attaching more wood to the corner, so that you don't cut through the 1/2" ply when rounding off said radiused corner!
And as a final note I have put the handle holes at the front on the base and diagonally opposite on the rear at the top. This means that when carrying, your legs won't bash into the speaker (something which happens FAR too often when dragging the things across fields!). Basically it is something like this:

It works an absoloute treat. I was going to buy handles, but after creating a test handle as per the plans, I thought it was so comfy, I just had to save the £€$ and go with the home made ones. Thought I'd share my handle planning train of thought - there was weeks of thinking that went into that - yet I still didn't quite leave enough room for those castors

They'll fit, but it will be a tight fit.
And finally... after buying a cheap (£37) router and using it toward the end of the build, they

rock! I only have a small 12 piece crappy bit set, but even with that and my cheapo router, it makes the build a) more fun, b) easier and c) much more pretty