I used the old 9mm floor to cut into batons then stuck in the gaps. I didn’t do them massive so they fill the whole gap like the pre made ones. I don’t know why you’d do that when it’s only to give something to fix into-I’d rather have that void filled with thermal insulation.
Then I covered the whole floor in dodo therma liner then put strips in all the low spots to give more thermal barrier.
I then bucked the trend by using 9mm ply instead of 12. I’ve got a low pop top and every mm counts. Plus, again, if your batons are the same level as all the metal ridges then where is this board going to flex?
I made the floor myself using 3 pieces of ply and the original floor as a template (plus some card to sort out the corners etc better fit than the original) and then screwed it down.
My conversion is a u-shaped arrangement so I did my cuts so that the walking area is the one large piece and one cut is under the offside units and the other cut is under the rear seat so joins will never be walked on.
Then I layed Altro flooring. I used Altro Xpresslay as you don’t need to glue the whole lot down with contact adhesive-you just use special double sided tape. A quick strip round the edge and a couple across the middle and it was done in no time with no mess. There’s been no movement and there’s no bounce when you walk on it-it feels like it’s bonded down.
I’ve deleted most of the pics from my phone.
