Thanks Lachlan and Svenedin
The post you directed me to appears to show that there are many opinions but little consensus.
I spent 30 years souping films by the book so now I have a little more time I want to explore the methods I did not try in the past.
Eventually I may settle down to a 'style'
OK, I'd suggest you carefully look at the contrast/time graphs & the characteristic curves on pp.5-6 of the
Delta 3200 datasheet, they'll tell you far more than a single random number from the massive dev chart.
The key point is that Ilford regards 'normal' development to be a Gbar of 0.62, which under a reasonable flare model will place 7 stops on to G2 paper - Delta 3200 is designed to comply with this model, not at its actual ISO speed (1000 in ID-11), but pushed to an EI of 3200. A development time in the low-mid Gbar 0.5 range may be more useful under contrasty light & Ilford suggest this will give an effective EI in the 800-1000 range going by the EI's on the development time table on pg.3. It should be noted that the graphs are given for DD-X & Microphen which can give up to 2/3 stop boost speedwise, but a great deal of the data extrapolates across.
Note too that Ilford don't give times for ID-11/Perceptol/Microphen at anything other than stock dilution - at the most essential level, this is because the film needs a decently aggressive developer to build contrast in a reasonable amount of time before the developer runs out of steam.
I hope this gives a more useful starting point for experimentation than expensively wasting your time & film on questions of agitation.