A couple of things you should think about:
Probably not a big issue, but reducing the power used by your instrument lighting will mean draining more power through your R/R which could shorten it's life. Hard to tell if the impact will be significant - not sure how many bulbs there are or what the wattage is - usually about 3 or 5W. So say, 6 bubs at 5W = 30W, Doesn't seem like a lot but one option would be to bump up your headlight wattage a bit.
Make sure the replacement LED's are bright enough. I swapped all the bulbs in my 900F cluster for LED's (the F bikes have an excited field alternator so there's a power benefit to running LED's - as opposed to total loss systems where power is generated whether you use it or not). The indicator LED lamps work fine and are bright enough for all round use but the instrument lighting LED are not really bright enough. OK for highway use at night but in town with all the incident lighting, not very useful (I had to put the odometer light back to a bulb as I couldn't see it with a LED).
LED's have polarity and a LED may or may not work in any given lamp socket. You can avoid this potential problem (I say 'potential' as it may not actually be a problem for Ascots) by ensuring your use bipolar LED's which will work with voltage of either polarity. If you're confident you know the voltage polarity at every socket then this isn't really an issue. Never the less, if you have mixed polarity sockets, using the bipolar LED's let's you get away with only one type of LED so dealing with spares is a little more convenient.
