Hi and thank you por your comprehensive answer. I understand what you say, I've illustrated a few books that have been published so far using default CMYK settings from Photoshop from my Imac and so far no complaints whatsoever from any client and accuracy once the book is printed is pretty good. I mean, what I see in the screen in Photoshop with CMYK preview is pretty much what I get in the printed work and never asked the client what CMYK profile they use.
However, with Clip Studio Paint, with the difault CMYK preview the colors are very washed, if I then open the same file in Photoshop with CMYK preview, the colors are much vivid. I have been playing around with it and find that the ISO coated Fogra CMYK profile in Clip Studio gives me far more vivid colors, always inside what is expected for CMYK, i.e. I don't expect the vibrancy of RGB colors.
To me working in RGB and convert in the last minute doesn't work, I just feel I have no control over the final range of colors.
I'll keep adjusting to the program or maybe, although that would be a pain, open the final illustrations in Photoshop for a final adjustment.
I don't think there is a way of doing that. If you make the ellipse on a vector layer, Ctrl will give the Object tool which can move the object and resize. Hold Shift and the aspect remains the same as you resize. Hold Alt and the center holds as you resize. Hold Alt Shift and center and aspect both hold.