What size compression springs for the 130p

[beamer3.6m]

I want to move my primary mirror up the tube so that I can achieve focus with a DSLR.

I could buy the 130pds but if I can solve the problem with a far cheaper spring replacement then I am at least willing to give it a go.

My question is what springs would I need to purchase and how do I remove the old ones???

[Alienfox]

I'm also looking to do the same mod and was hoping you would get a good response. 

[Macavity]

You might have to "think a bit" re. moving the focus? Meanwhile look at:

http://stargazerslounge.com/topic/188976-8-f4-newtonian-mirror-cell-mods/?p=2276693

Main credit to Laser_Jock, but I did manage to "root out" a few

extra (small order) suppliers of SPRINGS... and bigger knobs.