I made the sleeve patches 1/2 the size of my large patch and the pocket patch 1/4 the size of the large patch, but it really all depends on the max width of your sleeve and how large you're making your pocket.
Did you make sure the iron it down thoroughly? If you can see bubbles in it before cutting out the fabric shape, then you didn't leave the iron on top of the fabric long enough or the iron itself wasn't hot enough.
I haven't have any bubbling yet on mine so far and it's been over a year.
Also, did you make sure to pre-wash the fabric? When using things such as iron on or heat-n-bond, to get best merging results, pre-washing the fabric is a must.
ah, thanks! i actually found the problem, and it wasn't to do with how i was ironing the patches, but how i was stiching them. when i went around the curves at the bottom, i'd do it all as one continuous stitch, which would make it warp and bubble at the edges and then not sit down right. just doing each side of the emblem as a seperate pass seems to help fix the issue~