Unfortunately you can't use bumperettes with the 4 plus carrier. I asked Dave this very question about a year ago. I like that it mounts to the existing bolts, but also really like the look of the bumperettes. So for now it's stock carrier and bumper until I figure something else out.
Dave delivered the same news to me when I inquired. Right now I think I can get away with the mounted tire carrier, but that is step "T" and right now I am still at step "A" or "B" in terms of dealing with the tub.
@White Stripe, I went back to look at the picture that I posted of the truck's backside with the modified sill. From the picture it may look like there is a gap (black line) between the rear floor and sill itself -- that is actually some form of adhesive or sealant that was applied between the two pieces. I took a picture but for some reason I could not rotate it. . . so you will have to rotate your head to see it properly. I put my thumb over the black area -- in person it does not look terrible. I was trying to figure out what turned you off about the picture and this was all I could come up with.
I know this is not how the tub was designed. . . but this is what I have to work with and if all the pieces continue to fit as they should I can live with it. When I started I simply wanted to swap a Chevy I6 engine out of one truck for the proper Toyota engine. As it often happens with me the situation spiraled out of control to the point we are at now. I just want a truck I can bounce around town and a few light trails in. . . if I am kicked out of the club for a goobered up rear sill then I never wanted to be a member to begin with. I completely understand what you are saying though and I do appreciate your comments -- you speak your mind and you are direct with your words which I like.
Speaking of things getting out of control, last year I found another local project truck that started to be torn apart and the owner lost interest. Engine was pulled and partially disassembled. . . and that is how I bought it. I have been using it as a template to see how parts go back together when I did not take sufficient pictures during disassembly on mine. I gave it a look over today to see how the ambi doors line up on it compared to my before pictures. . . the center line across the doors lines up with the line on the hardtop sides in both trucks (see post #264 above). I still cannot figure out why the PO made the changes -- if he lowered the hardtop sides then I would think the hardtop itself would not line up with the windshield frame/front doors

. I am sure I will discover the answer sooner or later. . .
I did some head scratching for other reasons today as well. I rummaged thru the parts pile sent along with my current truck and filled up a bin of little pieces including the wiper components, mounts for the windshield rests, and all the bolts that came with the aqualu tub kit in little plastic boxes (among other parts). Hauled them into the shop for their turn(s) at being brought back to life.
I also started laying a few pieces out on the tub to get an idea of how things will fit moving forward. I better wear my skinny shoes when driving as there is not a lot of space between the trans hump and the gas pedal!
There was also a special guest in the shop today. Grandma TractorDoc celebrated her 90th birthday yesterday and she stayed over at the farm for a couple days after the big party. She wanted to come down to the shop for awhile today to see what I was working on over the last few months and wanted to make sure everything was going back together correctly.
She says she is pleased with my progress. She also wanted me to point out that I get my eye color from her

.
Right now the future plan is to aim for a window to get the front pieces painted. As that is going on I will continue to work on fitment/placement of pieces in and around the tub. Sounds simple but it has my brain pulled in so many different directions it can be difficult to focus.
Every now and again I like watching the car shows on the television. . . the Monkeys down in Texas make me laugh. I have no idea how they can crank out a finished vehicle (or even paint) as quick as they do -- I know its their job, they have experience, and they devote a lot more continuous time as a team; the magic of Television also condenses everything down to a couple hours too. If they tried filming an episode of "TractorDoc Garage" it would take over a year to produce an hour episode. I can see where it gives the average guy with a couple wrenches in his garage the idea that he can do it too. . . but it works out for me because those are usually the people I get my projects from!