For the finest of details you will need to go smaller. I would recommend getting a 1/8shank collet and a small set of ball nose bits for this type of application. If you add vectors to parts of the model you could do portions of it separately with different toolpaths or use a vcarve by only cutting inside the selected vector area that you want to cut.
Vectric VCarve supports automatic creation of clearing & finish paths using multiple & increasingly smaller bits. Each successive bit carves just the parts that couldn’t be done by the prior bit. You won’t end up doing the whole job in your smallest bit.
Ah, that’s the solution then. Carveco Maker has a roughing and finishing path built into their relief toolpath, but it still runs the bit across the entire relief instead of only the areas that the bigger bit missed.
If you look at the 3d carving I did in the finished projects the project was a 12x9. I ran 1/4 endmill roughing bit 260ipm in a roughing pass by itself 10min 18sec. Then a 1/8 endmill also roughing pass in separate tool path bit at 145ipm cut time 52min, last was a finishing pass using 1.0mm ball nose 1/8 shank at 60ipm total cut time 2 hr 55 min.
Total cut time for the whole project was only 4 hrs. With the right setup and speeds dialed in you should not run into carves lasting that long even using small bits.
You can mimic the same thing that vcarves rest machining will do and carveco’s model resolution is better than vcarves so it wont get better going there.
I would use a 1mm radius 1/4" ball nose bit for fine detail. You can also use a .5mm 1/4" ball nose bit for extremely fine detail. I run mine at fastest spin speed on the Makita. I believe that VCarvePro 11 now has a feature that will allow the finish cut to only carve the places where the roughing pass could not fit for the final detail. Have yet to try this myself. Up until now, I have just used the ball nose bits for the entire carve to save time rather than carving the entire piece twice. At the right speed these bits can take it and produce great results.