Bicycle Mechanics - Ultegra 6603 Brifters (3sp/10sp) Compatibility with 3sp/8sp

I'm looking at getting a pair of ST-6603 brifters for use on my touring bike. I currently have an older biopace triple upfront, and a 8sp cassette in back. I will eventually be upgrading to a 10sp cassette.

My question, can I use the brifters with my current drivetrain and just not have the last two "clicks" on the back? Or will the ratios be all off on the rear cassette? Seems like SB states that generally they are forgiving enough that they would probably work (for about the month or two before getting the 10sp cassette). Also will the triple front work with my biopace triple (its old).

If they aren't compatible, is there anything against using brifters only as aero brake levers (and not even have the shift cables attached), is anything going to get knocked loose as a result of not having tension on the shifting segments of the levers themselves?

Its just not in the budget to get a new cassette (or necessary) at the same time I get the brifters.

Thank you!

8-speed and 10-speed cog spacings are so different the chances of getting even remotely acceptable shift performance is slim.

Since the brifters are by far the most expensive single component, why not buy the 10-speed cassette and 10-speed chain and do it right from the beginning.

The triple may or may not work with your Biopace crank but try it and see.

Because for a very limited time I can get a really good deal on brand new Ultegra brifters, like around 50% off. Depending on contracts coming in I may be able to get the cassette and chain (which are both less than 2 months old on my bike) but I'm not sure yet.

Is there a problem if I use them as aero brake levers and mount the shift wires/etc later?

nope, not really, but they are easier to shift when there's no shifter cable installed.