I've done much the same.
Just get good quality swivel wheels and since the
finished car is around 900Kg, divide that by number of wheels you need.
Doesn't hurt to over engineer, besides, a larger rating wheel will also be far better quality and gives you a nice safety margin.
I used 4 x 75mm nylon wheels [screwed to a wooden pallet] each with a rating of 250Kg.
I only ever intend to use the dolly for a empty shell but I know it is up to the task if I want to trial fit anything else
I've also got a set of 4 of these little blokes: -
Attachment:
![[ attachment ]](./download/file.php?id=18432&t=1&sid=8c5ec65dd1dd4fb8f268d4daa404b4ba)
wheel trolley.jpg [ 242.72 KiB | Viewed 743 times ]
They are great but you need a very smooth floor to use them easily.
The car is still very heavy and it takes a lot of effort to shift it around.
These appear on eBay now and then, very robust and not real expensive
![Wink :wink:](./images/smilies/icon_wink.gif)