Aye welland99,
I used NJB shocks when buying replacements for the Morini 125H. These are non-adjustable and NJB fitted springs of a suitable rate for my weight and general riding style on the wee 'Morini the Minx'. They have performed well over the limited mileage that I have used the bike, and have handled all manner of A to Scottish un-classified road undulations!

The price was reasonable and the painted finish OK as is the chrome on the springs.
In my opinion NJB or Betor are perfectly adequate for day to day use on a range of road types. I used a set of Hagons on the Duke 450 single and they were leaking within 14 months of use, albeit daily use, but the 12 month 'warranty' had been passed and I have never used their products since. However, many Classic racers use Hagon products and find them fine, I would query their durability.
As for the length of the shock, convention is to measure the distance between the centre of the eyes at either end of the shock. The different mounting bolt diameters are accommodated using different bore rubber inserts and tubular steel inserts within the rubbers. If you choose to use the suppliers I suggested in my previous message, speak with them on the phone, with your specific requirements, the same with NJB and they can then give you a specific price for shocks set up to your specifications.
I hope this helps, my regards, Bill