alot of how your army is organised will depend on which army is the 'parent'... if you're wanting both assassins and daemonhosts, then use the daemonhunters as your parent list. (if the guard are your parent list, you don't get many elites choices!)
which ordo you choose really only affects wargear & retinues - radical daemonhunters may still take sisters of battle as allies too!
and i heartily agree with guard master; don't go all out on wargear for your inquisitor and/or inq.lord! infact, don't give him any close combat weapon beyond a simple power toy or lightning claw!
the problem is, daemonhunters pay space marine pts costs for their kit, making them horribly over-priced for what is still just a basic human character... (phil assures me this will be fixed when the codex is redone though, as he's also rather p*%#ed about it!) concerning psychic powers, nothing beats holocaust! so much fun dropping a pie-plate on top of an assaulting unit of say, oh... 20+ hormagaunts?!
as for your inquisitor's retinue, again keep it more shooty with a few acolytes to act as bullet catchers! (i personally would take 2 heavy bolter servitors along with a vet guardsman w/flamer for general 'shooty-burny' death!!!)
again, as pointed out taking inducted guard will give you lots of numbers and tank hunting ability which is something the daemonhunters serverly lack.
2 sentinels with lascannon & armoured crew compartments are tasty!
however, you're going to be limited to only the very basic guard units so plan on taking a couple of infantry platoons. heavy bolter/autocannons and grenade launchers are the best upgrades for guard infantry as they are reall ment to take on enemy infantry! wasting 9 other blokes just to miss a tank isn't that smart a move... i'd ignore the option for armoured fist squads as your own inquisition storm troopers are much better.
so basically, your guard units will for form your fire support while your inquisition units advance fowards and tackle the objectives. the one exception is the russ! give it the 3 heavy bolters it can take and this baby is just plain mean and will make a very tasty spearhead for your mobile units!
pm me with your e-mail for those radical wargear rules, or else you can find them in US white dwarf 287... (and that nice man mr.kelly has indeed promised his loyal brethren some more tasty treats when the codex is redone.
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cheers!