300mm MACRO len ???

some of the bugs/insect just too shy or sensitive to be get close and that's the time I am keep thinking of longer macro len with >1:1 magnification (as for now only Canon MPE-65 do that with 65mm ... hmmm )... that's why I have SIGMA 150 F2.8 macro too but then 150mm is just not enough for some case and I am start think of 180mm ... 200mm (minolta & nikon have it)

but then I used to add tele-convertor (1.4x) on my 150mm then I have 210mm :D ... which is really a good reach (ignore the lighting issue for longer reach). Last week, I have another idea to try out my 2x TC which bought and stay in my drybox for age ...and here I got 300mm Macro len with 2:1 magnification ... lOl but then I start worry of the TC soften effect on my picture but then it came out quick acceptable .. and what would you say (on the 1000pix picture quality) ???

both pictures below non crop, curve increase contrast, increase saturation & smart sharpen (at same value)

SIGMA150 + SIGMA 2x TC


SIGMA150 + Kenko 1.4x TC


so .. should I continue use the 2x ??? and I have 300mm macro len now :D