NRF
I would stick with the 25hrlys myself unless youve got a filter kit like HeliMatt has suggested.
The lycoming engine operation manual says for a 540 that at 75% power it should burn about 0.7 of a quart of oil per hour and this works out about true.
for the wash we use Truck wash also its good stuff and will do the job your looking for. windows we use a perspex cleaner or windex does the job fine!
all the best with your new machine!!