A useful "trick" for insects, flowers, etc., and windy conditions is to use a wire frame attached to the filter ring, (usually not fitted on digital compacts, but see below).
Use a dedicated close up lens, or a tube/bellows, for the higher magnification, and make a four pronged ring to fit the front, and trim the four wire "prongs" to the exact focal plane at max aperture, plus a small extra amount to allow adjustment. If the ring can turn to align the wires to the corner of the frame, all the better.
The wires are spayed out to clear the frame, and then small wires are then added between the protruding ones, just a shade inside the focal plane distance, all just beyond the frame edge.
The reason for the extra wires is to allow the stem of the plant to rest on the wires, stabilizing the flower and or, insect, against the breeze or wind. I carry extra fuse wire to add between the bottom prongs to wrap gently around the stem.
The reason this device is so useful is no reference to the camera viewfinder is needed at all. The wire frame provides the picture frame limits, and the focus, all done very accurately indeed. Use an enlarging lens and medium stops and the results can't be bettered.
Even better, you can drape a black cloth over the wire frame as perfect lens hood, or cover with thin white handkerchief to make a diffuser to soften the light. and it all works with film or digital!
For compact digital cameras, make a wood plate to fit under the camera via the tripod socket, and add the wires in the same way.
Ingenious device. I patented something on these lines for use in intra-oral photography. don't need to look through the camera, just point it at the patient's mouth and bingo. There was an adjustment for use with a palatal mirror. It was available in autoclaveable stainless steel or single-use plastic. Mine was an attachment to a Cokin filter holder.
I made an improved bitewing holder but that's another story.
Some of the old camera makers had close-up sets which used the same method as yours. Obviously the cloth and diffuser are your idea.
I only occasionally shoot macro. But I discovered a review about a macro lens was both extremely sharp and relatively inexpensive:
It is in the optical department that the Phoenix 100mm f/3.5 macro lens shines. It is really quite sharp, with excellent center resolution, and pretty good at the edges. Stopped down to f/8 or smaller, there is very little to pick between this lens and more expensive types. It does not match the superb Tamron 180mm f/3.5 macro but it certainly is on a par with the Nikkor 28-105mm f3.5-4.5D IF AF in macro mode, and much better than that lens at the edges. It is possible to count the hairs on an insect's body, though they don't show the hard-edged crispness of the Tamron or a micro-Nikkor.
Mounting the 1:1 adapter (a 49mm screw-in two-element filter) allows the lens to focus in to life size reproduction. Again, once stopped down the results are quite respectable, especially in the center. The edges are quite acceptable.