I do not own a Samyang 8mm Fisheye Lens, but I am still responding to your question because I do think that my comments will be useful to you.
I am not exactly sure what you mean by this phrase (my bold and underlinde): “Hubby and I both share his Canon Fisheye but it doesn't give me the full circle fisheye photos that I like.”
However I think that you might mean this . . . Example:
If you want to create Circular Fisheye Images with the Optical Circular Vignette, such as in the example above, then note well that the Samyang 8mm Fisheye Lens on your 60D will not do that.
Further, it occurs to me that the mentioned “Canon Fisheye” which you share with your Husband, is in fact the EF 8 to 15 F/4 L.
If you want to make fisheye images with a circular vignette (as per the example), then you can achieve that goal by using the 8 to 15 F/4 L on a 135 Format Camera (aka “Full Frame" Camera, such as a 5D or a 6D) and set the Fisheye Zoom Lens to FL = 8mm.
On the other hand, as it seems that you do already own arguably one of the highest quality Fisheye Lenses ever made for an EOS Camera and if you do not want the Optical Vignette, then instead of spending money on another lens, then I suggest you consider buying a 5D Series or 6D Camera.
WW