Ok after opinions here.

With Baby number 5 due in april, I am thinking of seating options in the car.
Currently I have 2yr old & 4 yr old in 5 point harnessed seats. 6 yr old in full back booster with adult belt & 8 yr old just on the seat.
I had it all planned in my head to have this baby in a capsule in the middle of the middle row of seats with 8yr old & possibly 6 yr old either side. then 2yr & 4 yr old on the back row (as they already are).

My idea with the capsule was so I could have baby rear facing for as long as possible (over 12 months) by getting the SnS unity capsule which goes to 12kg. My last boy was 9lb 9oz & I am expecting another boy & preparing for another biggy (I know its not a given, I am just assuming). BUT in saying that my kids have all followed a similar pattern in growth & hit the 10kg makr by 6/7 months & then stay around that till about 18 months. So I fully expect I will be able to use the capsule for over 12 months with the weight being up to 12kg.
My thought was, with the 2 littler kids needing to be buckled up still, I could put baby in the capsule while not in the car. Place capsule on the ground etc while I buckle the older 2 in & then older boys can get into seats, put on seat belts & then I can put in capsule & away we go. Reverse the process when we get to the destination. I am thinking this as I would like baby to be in the middle. Being in the middle rear facing while mean the kids/myself will have to climb around the read facing seat, but if its a capsule I can wait till everyone one is in & buckled before putting the capsule in. Follow what I mean? I also figure with the baby safely already buckled into the capsule, I wont have to worry about children running around the car or fumbling around while holding a baby which sorting out the others.
I don't plan on using the capsule to transport bubs around the place other then from house to car to house & possibly at school pick ups as the boys school is crazy busy & has really poor parking so I often have to park a mile away & walk to collect the boys(Although I am looking into getting them to catch the bus home in the afternoons or using the kiss & go zone, but they are only new to the school & unsure about where they have to be to use these options just yet & with Evans anxiety, it may not ever eventuate for him, getting lost is a big issue for him atm so I don't want to push it just yet)

SOOOOO What do you think, is the capsule a good idea or should I just use the rear to forward facing seat (which is also rear to 12kg) & have everyone move around it?
See I already own that seat, but not the capsule which I have found online for $270 inc postage. But what if I don't like the fit int he car, or have issues with it & need to return it? But if I buy direct from a baby store here its $100 more. Also im not sure even if 6yr olds booster will sit next to it with easy access to do his seat belt up so I possibly also like to put the 3 middle kids across the back which means buying a more compact 5 point seat for someone to fit in the middle (see my car only has lap belts in the middle so to use those belts it needs to be with a 5 point seat that doesn't need the shoulder bit to restrain the child kwim? I could buy a H harness but not keen on those)

So what are your thoughts?