I have been using 3/32 (some time referred to has #3 ) for years/ I just got some .008 shrink.
There is very little difference . If you work at it you can slip the .008 into the 3/32 shrink (note the word work) so it is smaller.
One thing that will help you is to roll joint with your fingers just after you remove the heat.
Also- plan your cuts- I splice then hook to components , this lets you roll the shrink and make the joint smaller.