For anyone considering buying an original Michell Unisweep base, you need to be aware that there are at lease three different bases that look like the correct base, but they are slightly different. I have all three and have compared them here so you will know what is what. The stubby height base seems to be the most readily available base. If you have any questions feel free to ask!
In addition, thanks to OdiWan72 and all of his help in acquiring these, I now have enough of the original spikes for all the pieces I want to make!