Tried to use the combo but my TC-17E only fits my 70-200 and 200-400 my 105 is unfortunately nor a VR - back to the drawing board!
As 'Interstatetime' / John Cote, another consummate professional, in an earlier post, re-iterates thoughtfully, successful photography is NOT about equipment - It is about the approach you take to experimentation, playing around, having fun with, & understanding how you can manipulate the intensity, & the passage of light, & it's reflection back, to achieve a spectacular result.
To be quite honest, sometimes a good 'Compact Camera' with a proven bit of 'melted sand' at the sharp end, will easily outperform high end DSLR's simply because of the freedom of movement, it affords the photographer to pan fluidly around the subject, changing angle, catching specular light 'crossing & catching' a crucial element of the design.
Who needs 12+ inches of murky lens barrel / converter between them, & their subject ?
In terms of stability............A large ( & cheap ) bean bag will often provide all the 'grounding' you need, one you have found the 'sweet spot' - that marriage between light, & angle, that you will instantly instantly recognise, when you find it.
Although I have Nikons / 'Blads - I very often use a compact Leica D Lux6, when shooting watches in macro, then PhotoShop to tidy up the composition, raise contrast, & sharpen. ( rare with a Leica ! ).
Stop planning, & accumulating pointless kit - Just cut loose, & shoot lots, & lots, & lots, of images in different lighting situations ( never on-camera flash !) & learn far more through viewfinder experience, & careful investigative review, then ever you will derive otherwise.
My credentials for such arrogant claims, are 25 years as a high end Advertising / Fashion photographer in the UK working for 'Blue Chip' clients across Europe - I now teach 'Creativity', to Adult University Students.
