Sue and I were playing with a static warm up a few weeks ago - worked for me as I did a 4min PB! And it worked for Sue as she did a good comp hold!!
Warm up inhale hold, just to get head in hold your breath mode - as long as comfy
4 min breathing
exhale hold for as long as comfy (about 1m 15 in my case)
4 min breathing
exhale hold for as long as comfy (about 1m 35 in my case)
6 min breathing
Go for it!
(Sue added another hold between the 2nd exhale hold and the 'go for it' hold - I tried that first time, but did a crap 'go for it hold'!)
Donna