Hi Bruce , and welcome , if it was me that had the HEQ5 mount I would grab the 100ED , 10mm is a lot at this size and the Black Diamonds get rave reviews every where on their quality of optics and build .
Nothing wrong with the WO 90mm , but as I said 102mm in a refractor hits the sweet spot , nice scopes .
Only a small step down in views on the TAK's , TV's , TMB's etc... out there in quality of optics .
These 2 together would be a long time partnership .
. Nice .
My 5c .
Brian.