David,

If it needs a valve job, it needs a valve job, and there is no future in worrying about any problems with increased compression. If you are trying to get by without doing the valve job, you can get some idea about the valve condition by turning the head upside down and filling the combustion chamber with some thin liquid like kerosene to see if the valves leak. You could use gasoline, but don't smoke near it. If they aren't too bad and if money is tight, you could do a poor man's valve job; i.e. hand lapping.

Don't worry about the T-belt being removed from the cam gear. You have to set that up when you reassemble it anyway. There is no way you are going to disassemble that much stuff and have everything remain in the same place.

No, don't cut up the T-belt cover. I assume you are going to replace the t-belt, so you need to take the crank pulley off anyway. If you aren't replacing the t-belt, keep tension on it so that it remains in engagement with the crank and intermediate shaft. But, it's probably too late for that anyway.

If you are going to use the rope trick to get the crank pulley off, you have to do that before you remove the head. Since the t-belt is off, make sure the valves are closed on the cylinder you choose for the rope. Are you making use of the 700/900 FAQ section?

Charley