hi neil, sounds like youll have no problems with the project

id be tempted to go with an ER11 C8 with a little less overhang

http://www.ebay.co.uk/itm/ER11-8MM-S...item231507033b

if you compare this with the one you linked i think youll know what im driving at... it may make little diffrence when cutting balsa but when aiming to cut ali every little bit of stiffness you can gain will help (i have cut ali with mine)

iv used cheep skate bearing in my ER C8 spindle... iv used belleville washers to put some tention between the two outer races.... i havnt had to change them yet but it only gets light use

if you dont put any tension on those skate bearings the balls will skid and self destruct pretty quickly

Click image for larger version. 

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the layout is not to clear in this picture, youll have to let me know if you dont get it