It is possible to get the lens modified by a competent engineer. I had a 35mm non AI lens converted and all that was required was a step to be machined in the back ring so that it will couple with the metering ring. It won't cost a lot of money and save you getting rid of what is a good lens.
The stop down metering is not that bad.
The 135mm requires a different style of shooting takes a lotta practice.
I only use one for static scenes or panning horsie on jump or auto on track or people at weddings.
If you google one of the repair people may have a factory ring or a spare converted using a nail file will reduce value, keep the original.
Something you may wish to look into is an AI conversion kit for that lens. This will a) allow the lens to couple to the camera's meter and b) allow you to see the F-stop in the viewfinder - the conversion kit consists of a replacement aperture ring and can be exchanged for the original in about 10 minutes by a competent technician.
I'm pretty sure all Nikons of the AI and later age have the aperture display read off the aperture ring. I saw recently, somewhere, a list of factory AI conversion kits for sale NOS. I'm trying to recall where.
If you get the chance, glom one of the factory kits. I'll post the link if I find it. I have a pre AI 28/3.5 with the factory ring on it and it works perfectly on an FM2n - meter coupling and aperture readout. The only issue with the stick on scales is that the numerals are relatively tiny and it must be placed precisely on the aperture ring for it to align properly.
If all my (other six Nikkor) lenses had the conversion ring I'd be in the market for an FM2n, they're quite the nice little camera.
When you are in action and you don't have time - just shoot wide open
That what I was relizing. With the extra step in aquasitioning the image. Not much for fast moving objects. I attending to use this lens for portriat work.
The lens is f/2.8 and you want to shoot at say f/5.6 you have to stop the lens down 2 stop. Well turn the ISO down 2 stops or turn the exposure compensation up to +2. Set the lens at f/5.6 and just shoot in A mode. The camera thinks that you are shooting wide open and measures the light at f/2.8 but you dial in the compensation it would give you correct exposure. No need to push the DOF level.
I posted on Lens thread that I tested a roll on a co-worker and her little boy. They came out amazing . The Negs had exposure consitancy and very tack sharp (For 35mm). The lens is one of my goto lens in my bag now. Thanks again for the help.