Well allowing urself the extra few hours as u put it still means two days, and if you're supplying mats as well, then it's certainly NOT expensive!
9m2 that's 3 bags of addy, about £45 plus grout, (another £15) leaves you £230 for two days. Cos whether or not it's a few hours it's stil another day isn't it!
What about expenses? D'u have parking to worry about, fuel, is it nearby?
Wouldn't be enough for me.
If you're happy tho Terry, then go for it mate.
So how did you do on that slate job? Honestly now!
How long did it really take you?