Dont use a generic, it will slip and cause damage / harm. Look on the GoMog website for details. I use 2 x 6mm threaded rod and wind down the spring. Cost about £5
This method works well, I have used it many times without any trouble

https://www.gomog.com/allmorgan/frontsuspension.html#TOOLS


"DOT" 35th Anniversary Edition Plus 8- family owned from new. Rolls Royce Pewter.
06 Saab 93