If you move the tank around you will disturb sediment, but as long as you have a decent fuel filter fitted it should be fine. I have a chrome/glass cleanable filter on the rubber pipe in the boot on the fuel pick-up, this stops any debris as soon as it leaves the tank so protects the fuel pump as well as the carbs and is easily accessible for cleaning.
In addition you could take the opportunity whilst the tank is out of draining and cleaning, www.frost.co.uk sell various products to clean, prep and even seal the tank if you feel the need.
The second article that Casper has linked to is mine, I can't tell you how much easier it is to remove & refit the tank without the drain plug. If you get carried away and decide to have the drain removed, be very careful. There are obvious risks in welding fuel tanks so give it to a professional if you're the slightest bit unsure, mine hadn't had fuel in it for a very long time so decided it was safe, but even so I was still a little nervous when doing it.