Are there furniture items that conflict with each other

Save the game, press 'T' to check the day and time, fast travel to the place, press 'T' again to see how many days have passed. That will tell you how long the fast travel time is between those two spots. Re-load the save if you aren't happy with your purchase.

Here's a small exmaple of how DPS works in Skyrim. The DPS if smithed row shows how DPS will change if all weapons get the same smithing bonus damage of 46 (smithing gives a flat increase to damage instead of scaling to base damage)

Weapon              Damage  Speed   DPS     DPS if smithed
Deadric sword       14      1       14      60
Deadric greatsword  24      0.7     16.8    49
Deadric warhammer   27      0.6     16.2    43.8
Deadric battleaxe   25      0.7     17.5    49.7
Deadric dagger      11      1.3     14.3    74.1

As you can see, the weapons are more or less balanced without smithing, but with smithing speed wins over base damage every time. I'd recommend one-handed weapons unless you're not interested in smithing or not obsessed with having the biggest numbers.