Canon FL-F vs. Apo-telyt suggestion

[Ago73]

Hi guys, I have been on this forum for a quite long time but this is my first thread.
I'm a micro 43 user (GH2 and OM-D) and I'm quite interested in using MF lenses.
I currently have the Apo-lanthar 125mm and I'm very happy with it. Last year I bought a Mamiya Apo-Sekor 200mm 2.8 and also this is a very nice lens, very good colors and great sharpness. However, for my personal usage it is a little bit too heavy (very front-heavy) and I would like to have some more reach (I have the Mamiya 2X extender, but the compo is very long, almost 30cm), so I'm looking for a 200mm+ light-weight telephoto MF lens.
Light-weight lenses are usually not very fast, but I'm OK with slow lenses if they can provide very good IQ wide-open.

I'm currently evaluating these 2 options:
- Canon FL-F 300mm 5.6, good sharpness and CA, but I found very few info (apart the post by Abbazz of 2009)
- Leica Apo-telyt 180mm 3.4 + APO 2X-Extender

It's hard to find 100% crops for a good evalutaion of the sharpness, so I would like to ask your suggestions about these 2 options. For the Canon option, I'm a little bit scared by the fact that the lens is very old and I'm not sure about his rendition, in particular the flare control (poor coatings). Apo-telyt has a strong reputetion at long distances, with the extender it becomes f/7, so it might have very good IQ already wide-open (no need to stop-down for optimal performances).

Thank you for any advice you can give.

[calvin83]

If you can stand the lack of aperture and donut bokeh, the Minolta RF Rokkor 250mm F5.6 is your choice.

P.S. It costless than $100 ten years ago in my city but it cost $1000+ now.

[iangreenhalgh1]

Small, light, superb - Topcon Re Auto Topcor 5.6/200.

[Ago73]