Should the horseshoe for a West entrance be fixed inside or outside the door, and which way should its mouth face?
Fix it outside the door. Hang it in a U shape, exactly the way the English letter U is written, with the open end upward.
Related questions
A rectangular plot is built up on three sides and open only on the West, so its energy is low. How can it be extended?
Do not extend it. Instead, place energy-giving items and capture the energy from all four sides to raise the energy level; this is covered in the energy chapter.
If Saturn is debilitated, can a shami plant be grown?
No; why invite spirits? One person planted two shami trees in the West of his home believing it would help, faced three to four months of trouble and returned them to the gardener. Shami should not be grown at home.
If doors are already open on wrong padas, how are they treated in interior vastu?
Vedic vastu says the defects of a wrongly placed door can be removed through the decoration of the door itself: auspicious symbols, yantras, paintings and artworks made on the door, door power at the threshold, and a bandhanwar (toran) hung on it. This class therefore treats wrong doors with symbols, torans, bandhanwars and colours rather than structural changes.
If the main door is on a negative pad, does a clockwise or anti-clockwise route to the boundary gate change its results?
Yes. A correctly placed door with an anti-clockwise (heen bahu) exit gives fewer good results than it should. A door on a negative pad such as E5 or E6, whose route runs clockwise to a gate on W4 or W5, gives much less negative effect than the pad alone would.
In the seven sea-salt lump usara of the main door, are the rounds made clockwise or anti-clockwise?
Clockwise only. Standing outside the main door, circle the hand holding the seven lumps clockwise in front of the door for the rounds, then sweep once or twice from the front as if pouring the energy out and throwing it away outside. Do it only while the right nostril (Surya swar) is active; done in the left swar it gives no result and instead invites negativity. Swar vigyan is the base of everything, and without swar, vastu is handicapped.
Must the house be at 0 degrees for a sarvatobhadra dwar?
By definition it is at 0 degrees with doors in all four directions, but it can be made otherwise too: build the doors on whichever pads fall on Pushpdant, Grihakshat, Bhallat and E4.