As an
IW player I always envy you your great special rules - 2+ hit with bolters, tankhunters on HSS and deapstrike on termies. (Even more because
IW doesnt have any special rules, just special units. On the other go I have to admit that
IW special units are better.)
If I would field IF, I would concentrate on units that get your free upgrades and are cheap and effective.
Thus I would field a stone gauntlet and field 2 blobs of breachers, one blob of tacticals, 3 full squads of heavy supprorts. All with apotecaries. Then add some rapiers. Man, that would be great