I don't know what size prints you plan on printing but one never has enough sink space.
I would make the sink as large as you possibly can. Even if when you are doing dry work you put a portable cover over it. I have built a few darkrooms and I now stack my trays with a home made wooden stacking system. I print 20x24 mostly and have stacked dev, stop, fix 1, fix2, and hypoclear. In this manner I have only taken up the space of not much more that 20x24. The rest of the sink I have a permanent 20x24 syphon wash tray as well as a 20x24 print washer. I also have room to selenium tone or bleach and sepia tone at the same time. If I print smaller prints I just use 8x10 or 11x14 trays.
My point is, that the stacking enables me do all aspect at one time and the inconvenience of the stacking is quickly gotten used to.
Another thing I do is use Ilfostop, stop bath which is odorless, and I use plexiglas covers over my fix and selenium etc to keep down the fumes. I have pretty good ventilation but these two fumes are nasty and with the plexi covers I rarely smell them. I just lift the cover, slide in the print and agitate the trays.