Have you measured the foot print of you 6X6 enlarger and compared it to a 4X5? My current darkroom is a 2 sink bath, I have both a D3 and either a 6X7, 6X9, or 6X6 depending on needs and whims. The D3 is 24X18 the Metop 6X6 is 22X15. My D3 is on old metal computer desk, ceiling height is sufficient. Although it may take you a while, finding an old Federal 4X5 might work for you, the Federals are made from stamped parts, and will be lighter than an Omega, could be put up and taken down without much trouble. The old Federals will need to have lens board machined to take a modern lens. D2s are common, not expensive, but if you cant find in your local area shipping is high.