You can get those bushings from Lancaster Archery or from the DAS web site. It's real easy to change them out, but you need to "know" how to do it.
ILF bushings have to be replaced with the DAS bushings on the 17" DAS riser. The 21" DAS riser if offered to accept either ILF or DAS bushings.
You're right that you won't have the weight and tiller adjustability with the GameMaster that is afforded with the DAS and Titan.
I own both the Titan and DAS risers. You won't go wrong with either. If you're looking for a more "traditional" look and feel, you might want to check out the TradTech Pinnacle and Morrison ILF risers.