The only negative to this is that the aperture is probably being reduced.
These small reflectors usually have woefully small secondary mirrors that are often incapable of illuminating more than a very small field, maybe on the order of 2 or 3mm.
For every multiple of the focal length that you move the primary closer to the secondary, you decrease the size of that illuminated field by 1mm.
For example, if the fully illuminted circle is 3mm, and the focal ratio is f/5, them moving the mirror more than 15mm closer to the secondary will mean that you are at the start of aperture reduction.
Now none of this matters at all if you are content with the result, but if you have not ray traced it or measured the aperture in any way, then you really don't know what focal ratio you are working at.
Again, that means absolutely nothing if you like the result, but if you want to know if there is a negative consequence to your action, then this would be it. Is it negative enough for you to care? It seems that you have answered that question for yourself already.
Edited by Eddgie, 13 November 2019 - 12:58 PM.