Just a quick question

Im finally getting around to building a router but im not sure on the size of the supported rails and leadscrew.

I will be mainly cutting acrylic and alloy and teh design thats in my head should be very stable.

So would 20mm supported rails be ok for a 48" axis with a 20mm ballscrew, originally i was going to go for 16mm all round for the leadscrews but i think the 20mm may give me less whip at higher speeds.

Thanks Adam